打开终端
先做个备份（以防不测）
sudo cp /etc/apt/sources.list /etc/apt/sources.list_bak
然后
sudo gedit /etc/apt/sources.list
在打开的页面里面添加你的源：
Archive.ubuntu.com更新服务器（欧洲，此为官方源，电信网通用户使用)：
deb http://archive.ubuntu.com/ubuntu/ hardy main restricted universe multiverse deb http://archive.ubuntu.com/ubuntu/ hardy-security main restricted universe multiverse deb http://archive.ubuntu.com/ubuntu/ hardy-updates main restricted universe multiverse deb http://archive.ubuntu.com/ubuntu/ hardy-proposed main restricted universe multiverse deb http://archive.ubuntu.com/ubuntu/ hardy-backports main restricted universe multiverse deb-src http://archive.ubuntu.com/ubuntu/ hardy main restricted universe multiverse deb-src http://archive.ubuntu.com/ubuntu/ hardy-security main restricted universe multiverse deb-src http://archive.ubuntu.com/ubuntu/ hardy-updates main restricted universe multiverse deb-src http://archive.ubuntu.com/ubuntu/ hardy-proposed main restricted universe multiverse deb-src http://archive.ubuntu.com/ubuntu/ hardy-backports main restricted universe multiverse
Ubuntu.cn99.com更新服务器（江苏省常州市电信，推荐电信用户使用）：
deb http://ubuntu.cn99.com/ubuntu/ hardy main restricted universe multiverse deb http://ubuntu.cn99.com/ubuntu/ hardy-security main restricted universe multiverse deb http://ubuntu.cn99.com/ubuntu/ hardy-updates main restricted universe multiverse deb http://ubuntu.cn99.com/ubuntu/ hardy-proposed main restricted universe multiverse deb http://ubuntu.cn99.com/ubuntu/ hardy-backports main restricted universe multiverse deb-src http://ubuntu.cn99.com/ubuntu/ hardy main restricted universe multiverse deb-src http://ubuntu.cn99.com/ubuntu/ hardy-security main restricted universe multiverse deb-src http://ubuntu.cn99.com/ubuntu/ hardy-updates main restricted universe multiverse deb-src http://ubuntu.cn99.com/ubuntu/ hardy-proposed main restricted universe multiverse deb-src http://ubuntu.cn99.com/ubuntu/ hardy-backports main restricted universe multiverse
网易163更新服务器：
deb http://mirrors.163.com/ubuntu/ hardy main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ hardy-security main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ hardy-updates main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ hardy-proposed main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ hardy-backports main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ hardy main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ hardy-security main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ hardy-updates main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ hardy-proposed main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ hardy-backports main restricted universe multiverse
Mirrors.shlug.org更新服务器（电信服务器，Ubuntu China Official Mirror, maintained by Shanghai Linux User Group）：
deb http://cn.archive.ubuntu.com/ubuntu hardy main restricted universe multiverse deb http://cn.archive.ubuntu.com/ubuntu hardy-security main restricted universe multiverse deb http://cn.archive.ubuntu.com/ubuntu hardy-updates main restricted universe multiverse deb http://cn.archive.ubuntu.com/ubuntu hardy-backports main restricted universe multiverse deb http://cn.archive.ubuntu.com/ubuntu hardy-proposed main restricted universe multiverse deb-src http://cn.archive.ubuntu.com/ubuntu hardy main restricted universe multiverse deb-src http://cn.archive.ubuntu.com/ubuntu hardy-security main restricted universe multiverse deb-src http://cn.archive.ubuntu.com/ubuntu hardy-updates main restricted universe multiverse deb-src http://cn.archive.ubuntu.com/ubuntu hardy-backports main restricted universe multiverse deb-src http://cn.archive.ubuntu.com/ubuntu hardy-proposed main restricted universe multiverse
Mirror.lupaworld.com更新服务器（浙江省杭州市双线服务器）：
deb http://mirror.lupaworld.com/ubuntu hardy main restricted universe multiverse deb http://mirror.lupaworld.com/ubuntu hardy-security main restricted universe multiverse deb http://mirror.lupaworld.com/ubuntu hardy-updates main restricted universe multiverse deb http://mirror.lupaworld.com/ubuntu hardy-backports main restricted universe multiverse deb http://mirror.lupaworld.com/ubuntu hardy-proposed main restricted universe multiverse deb-src http://mirror.lupaworld.com/ubuntu hardy main restricted universe multiverse deb-src http://mirror.lupaworld.com/ubuntu hardy-security main restricted universe multiverse deb-src http://mirror.lupaworld.com/ubuntu hardy-updates main restricted universe multiverse deb-src http://mirror.lupaworld.com/ubuntu hardy-backports main restricted universe multiverse deb-src http://mirror.lupaworld.com/ubuntu hardy-proposed main restricted universe multiverse
厦门大学更新服务器（教育网服务器）：
deb ftp://ubuntu.realss.cn/ubuntu/ hardy main restricted universe multiverse deb ftp://ubuntu.realss.cn/ubuntu/ hardy-backports restricted universe multiverse deb ftp://ubuntu.realss.cn/ubuntu/ hardy-proposed main restricted universe multiverse deb ftp://ubuntu.realss.cn/ubuntu/ hardy-security main restricted universe multiverse deb ftp://ubuntu.realss.cn/ubuntu/ hardy-updates main restricted universe multiverse deb-src ftp://ubuntu.realss.cn/ubuntu/ hardy main restricted universe multiverse deb-src ftp://ubuntu.realss.cn/ubuntu/ hardy-backports main restricted universe multiverse deb-src ftp://ubuntu.realss.cn/ubuntu/ hardy-proposed main restricted universe multiverse deb-src ftp://ubuntu.realss.cn/ubuntu/ hardy-security main restricted universe multiverse deb-src ftp://ubuntu.realss.cn/ubuntu/ hardy-updates main restricted universe multiverse
成都市 电子科技大学更新服务器（教育网，推荐校园网和网通用户使用）：
deb http://ubuntu.uestc.edu.cn/ubuntu/ hardy main multiverse restricted universe deb http://ubuntu.uestc.edu.cn/ubuntu/ hardy-backports main multiverse restricted universe deb http://ubuntu.uestc.edu.cn/ubuntu/ hardy-proposed main multiverse restricted universe deb http://ubuntu.uestc.edu.cn/ubuntu/ hardy-security main multiverse restricted universe deb http://ubuntu.uestc.edu.cn/ubuntu/ hardy-updates main multiverse restricted universe deb-src http://ubuntu.uestc.edu.cn/ubuntu/ hardy main multiverse restricted universe deb-src http://ubuntu.uestc.edu.cn/ubuntu/ hardy-backports main multiverse restricted universe deb-src http://ubuntu.uestc.edu.cn/ubuntu/ hardy-proposed main multiverse restricted universe deb-src http://ubuntu.uestc.edu.cn/ubuntu/ hardy-security main multiverse restricted universe deb-src http://ubuntu.uestc.edu.cn/ubuntu/ hardy-updates main multiverse restricted universe == 如果无法解析uestc.edu.cn域名，请使用以下地址 == deb http://ubuntu.dormforce.net/ubuntu/ hardy main multiverse restricted universe deb http://ubuntu.dormforce.net/ubuntu/ hardy-backports main multiverse restricted universe deb http://ubuntu.dormforce.net/ubuntu/ hardy-proposed main multiverse restricted universe deb http://ubuntu.dormforce.net/ubuntu/ hardy-security main multiverse restricted universe deb http://ubuntu.dormforce.net/ubuntu/ hardy-updates main multiverse restricted universe deb-src http://ubuntu.dormforce.net/ubuntu/ hardy main multiverse restricted universe deb-src http://ubuntu.dormforce.net/ubuntu/ hardy-backports main multiverse restricted universe deb-src http://ubuntu.dormforce.net/ubuntu/ hardy-proposed main multiverse restricted universe deb-src http://ubuntu.dormforce.net/ubuntu/ hardy-security main multiverse restricted universe deb-src http://ubuntu.dormforce.net/ubuntu/ hardy-updates main multiverse restricted universe
上海市上海交通大学更新服务器（教育网，推荐校园网和网通用户使用）：
deb http://ftp.sjtu.edu.cn/ubuntu/ hardy main multiverse restricted universe deb http://ftp.sjtu.edu.cn/ubuntu/ hardy-backports main multiverse restricted universe deb http://ftp.sjtu.edu.cn/ubuntu/ hardy-proposed main multiverse restricted universe deb http://ftp.sjtu.edu.cn/ubuntu/ hardy-security main multiverse restricted universe deb http://ftp.sjtu.edu.cn/ubuntu/ hardy-updates main multiverse restricted universe deb-src http://ftp.sjtu.edu.cn/ubuntu/ hardy main multiverse restricted universe deb-src http://ftp.sjtu.edu.cn/ubuntu/ hardy-backports main multiverse restricted universe deb-src http://ftp.sjtu.edu.cn/ubuntu/ hardy-proposed main multiverse restricted universe deb-src http://ftp.sjtu.edu.cn/ubuntu/ hardy-security main multiverse restricted universe deb-src http://ftp.sjtu.edu.cn/ubuntu/ hardy-updates main multiverse restricted universe
中国科学技术大学更新服务器（教育网，推荐校园网和网通用户使用）：
deb http://debian.ustc.edu.cn/ubuntu/ hardy main multiverse restricted universe deb http://debian.ustc.edu.cn/ubuntu/ hardy-backports main multiverse restricted universe deb http://debian.ustc.edu.cn/ubuntu/ hardy-proposed main multiverse restricted universe deb http://debian.ustc.edu.cn/ubuntu/ hardy-security main multiverse restricted universe deb http://debian.ustc.edu.cn/ubuntu/ hardy-updates main multiverse restricted universe deb-src http://debian.ustc.edu.cn/ubuntu/ hardy main multiverse restricted universe deb-src http://debian.ustc.edu.cn/ubuntu/ hardy-backports main multiverse restricted universe deb-src http://debian.ustc.edu.cn/ubuntu/ hardy-proposed main multiverse restricted universe deb-src http://debian.ustc.edu.cn/ubuntu/ hardy-security main multiverse restricted universe deb-src http://debian.ustc.edu.cn/ubuntu/ hardy-updates main multiverse restricted universe
中国台湾 台湾大学更新服务器（推荐网通用户使用，电信PING平均响应速度41MS。强烈推荐此源，比较完整，较少出现同步问题）：
deb http://ubuntu.csie.ntu.edu.tw/ubuntu/ hardy main restricted universe multiverse deb-src http://ubuntu.csie.ntu.edu.tw/ubuntu/ hardy main restricted universe multiverse deb http://ubuntu.csie.ntu.edu.tw/ubuntu/ hardy-updates main restricted universe multiverse deb-src http://ubuntu.csie.ntu.edu.tw/ubuntu/ hardy-updates main restricted universe multiverse deb http://ubuntu.csie.ntu.edu.tw/ubuntu/ hardy-backports main restricted universe multiverse deb-src http://ubuntu.csie.ntu.edu.tw/ubuntu/ hardy-backports main restricted universe multiverse deb http://ubuntu.csie.ntu.edu.tw/ubuntu/ hardy-security main restricted universe multiverse deb-src http://ubuntu.csie.ntu.edu.tw/ubuntu/ hardy-security main restricted universe multiverse deb http://ubuntu.csie.ntu.edu.tw/ubuntu/ hardy-proposed main multiverse restricted universe deb-src http://ubuntu.csie.ntu.edu.tw/ubuntu/ hardy-proposed main restricted universe multiverse
mirror.rootguide.org更新服务器（上海市 电信）：
deb http://mirror.rootguide.org/ubuntu/ hardy main restricted universe multiverse deb-src http://mirror.rootguide.org/ubuntu/ hardy main restricted universe multiverse deb http://mirror.rootguide.org/ubuntu/ hardy-updates main restricted universe multiverse deb-src http://mirror.rootguide.org/ubuntu/ hardy-updates main restricted universe multiverse deb http://mirror.rootguide.org/ubuntu/ hardy-backports main restricted universe multiverse deb-src http://mirror.rootguide.org/ubuntu/ hardy-backports main restricted universe multiverse deb http://mirror.rootguide.org/ubuntu/ hardy-security main restricted universe multiverse deb-src http://mirror.rootguide.org/ubuntu/ hardy-security main restricted universe multiverse deb http://mirror.rootguide.org/ubuntu/ hardy-proposed main multiverse restricted universe deb-src http://mirror.rootguide.org/ubuntu/ hardy-proposed main restricted universe multiverse
台湾的官方源速度也相当不错，有时甚至快于内地的：
deb http://tw.archive.ubuntu.com/ubuntu hardy main restricted universe multiverse deb http://tw.archive.ubuntu.com/ubuntu hardy-security main restricted universe multiverse deb http://tw.archive.ubuntu.com/ubuntu hardy-updates main restricted universe multiverse deb http://tw.archive.ubuntu.com/ubuntu hardy-backports main restricted universe multiverse deb http://tw.archive.ubuntu.com/ubuntu hardy-proposed main restricted universe multiverse deb-src http://tw.archive.ubuntu.com/ubuntu hardy main restricted universe multiverse deb-src http://tw.archive.ubuntu.com/ubuntu hardy-security main restricted universe multiverse deb-src http://tw.archive.ubuntu.com/ubuntu hardy-updates main restricted universe multiverse deb-src http://tw.archive.ubuntu.com/ubuntu hardy-backports main restricted universe multiverse deb-src http://tw.archive.ubuntu.com/ubuntu hardy-proposed main restricted universe multiverse
#Ubuntu官方源
deb http://cn.archive.Ubuntu.com/ubuntu/ natty multiverse
deb-src http://cn.archive.Ubuntu.com/ubuntu/ natty multiverse
deb http://cn.archive.Ubuntu.com/ubuntu/ natty-updates multiverse
deb-src http://cn.archive.Ubuntu.com/ubuntu/ natty-updates multiverse
deb http://security.Ubuntu.com/ubuntu natty-security main restricted
deb-src http://security.Ubuntu.com/ubuntu natty-security main restricted
deb http://security.Ubuntu.com/ubuntu natty-security universe
deb-src http://security.Ubuntu.com/ubuntu natty-security universe
deb http://security.Ubuntu.com/ubuntu natty-security multiverse
deb-src http://security.Ubuntu.com/ubuntu natty-security multiverse
deb http://archive.canonical.com/Ubuntu natty partner
deb-src http://archive.canonical.com/Ubuntu natty partner
#Ubuntu 11.04台湾源（推荐）
deb http://tw.archive.Ubuntu.com/ubuntu/ natty main universe restricted multiverse
deb-src http://tw.archive.Ubuntu.com/ubuntu/ natty main universe restricted multiverse
deb http://tw.archive.Ubuntu.com/ubuntu/ natty-security universe main multiverse restricted
deb-src http://tw.archive.Ubuntu.com/ubuntu/ natty-security universe main multiverse restricted
deb http://tw.archive.Ubuntu.com/ubuntu/ natty-updates universe main multiverse restricted
deb-src http://tw.archive.Ubuntu.com/ubuntu/ natty-updates universe main multiverse restricted
#SRT Sources
deb http://Ubuntu.srt.cn/ubuntu/ natty main restricted universe multiverse
deb http://Ubuntu.srt.cn/ubuntu/ natty-security main restricted universe multiverse
deb http://Ubuntu.srt.cn/ubuntu/ natty-updates main restricted universe multiverse
deb http://Ubuntu.srt.cn/ubuntu/ natty-proposed main restricted universe multiverse
deb http://Ubuntu.srt.cn/ubuntu/ natty-backports main restricted universe multiverse
deb-src http://Ubuntu.srt.cn/ubuntu/ natty main restricted universe multiverse
deb-src http://Ubuntu.srt.cn/ubuntu/ natty-security main restricted universe multiverse
deb-src http://Ubuntu.srt.cn/ubuntu/ natty-updates main restricted universe multiverse
deb-src http://Ubuntu.srt.cn/ubuntu/ natty-proposed main restricted universe multiverse
deb-src http://Ubuntu.srt.cn/ubuntu/ natty-backports main restricted universe multiverse
#Ubuntu11.04网易源（速度很快、推荐）
deb http://mirrors.163.com/Ubuntu/ natty main universe restricted multiverse
deb-src http://mirrors.163.com/Ubuntu/ natty main universe restricted multiverse
deb http://mirrors.163.com/Ubuntu/ natty-security universe main multiverse restricted
deb-src http://mirrors.163.com/Ubuntu/ natty-security universe main multiverse restricted
deb http://mirrors.163.com/Ubuntu/ natty-updates universe main multiverse restricted
deb http://mirrors.163.com/Ubuntu/ natty-proposed universe main multiverse restricted
deb-src http://mirrors.163.com/Ubuntu/ natty-proposed universe main multiverse restricted
deb http://mirrors.163.com/Ubuntu/ natty-backports universe main multiverse restricted
deb-src http://mirrors.163.com/Ubuntu/ natty-backports universe main multiverse restricted
deb-src http://mirrors.163.com/Ubuntu/ natty-updates universe main multiverse restricted
#Ubuntu11.04上海源
deb http://mirror.rootguide.org/Ubuntu/ natty main universe restricted multiverse
deb-src http://mirror.rootguide.org/Ubuntu/ natty main universe restricted multiverse
deb http://mirror.rootguide.org/Ubuntu/ natty-security universe main multiverse restricted
deb-src http://mirror.rootguide.org/Ubuntu/ natty-security universe main multiverse restricted
deb http://mirror.rootguide.org/Ubuntu/ natty-updates universe main multiverse restricted
deb http://mirror.rootguide.org/Ubuntu/ natty-proposed universe main multiverse restricted
deb-src http://mirror.rootguide.org/Ubuntu/ natty-proposed universe main multiverse restricted
deb http://mirror.rootguide.org/Ubuntu/ natty-backports universe main multiverse restricted
deb-src http://mirror.rootguide.org/Ubuntu/ natty-backports universe main multiverse restricted
deb-src http://mirror.rootguide.org/Ubuntu/ natty-updates universe main multiverse restricted
#Ubuntu 11.04 搜狐源
deb http://mirrors.shlug.org/Ubuntu/ natty main universe restricted multiverse
deb-src http://mirrors.shlug.org/Ubuntu/ natty main universe restricted multiverse
deb http://mirrors.shlug.org/Ubuntu/ natty-security universe main multiverse restricted
deb-src http://mirrors.shlug.org/Ubuntu/ natty-security universe main multiverse restricted
deb http://mirrors.shlug.org/Ubuntu/ natty-updates universe main multiverse restricted
deb http://mirrors.shlug.org/Ubuntu/ natty-proposed universe main multiverse restricted
deb-src http://mirrors.shlug.org/Ubuntu/ natty-proposed universe main multiverse restricted
deb http://mirrors.shlug.org/Ubuntu/ natty-backports universe main multiverse restricted
deb-src http://mirrors.shlug.org/Ubuntu/ natty-backports universe main multiverse restricted
deb-src http://mirrors.shlug.org/Ubuntu/ natty-updates universe main multiverse restricted
#Ubuntu 11.04 骨头源 （bones7456架设的一个Ubuntu源 ，提供ubuntu,deepin）
deb http://Ubuntu.srt.cn/ubuntu/ natty main universe restricted multiverse
deb-src http://Ubuntu.srt.cn/ubuntu/ natty main universe restricted multiverse
deb http://Ubuntu.srt.cn/ubuntu/ natty-security universe main multiverse restricted
deb-src http://Ubuntu.srt.cn/ubuntu/ natty-security universe main multiverse restricted
deb http://Ubuntu.srt.cn/ubuntu/ natty-updates universe main multiverse restricted
deb http://Ubuntu.srt.cn/ubuntu/ natty-proposed universe main multiverse restricted
deb-src http://Ubuntu.srt.cn/ubuntu/ natty-proposed universe main multiverse restricted
deb http://Ubuntu.srt.cn/ubuntu/ natty-backports universe main multiverse restricted
deb-src http://Ubuntu.srt.cn/ubuntu/ natty-backports universe main multiverse restricted
deb-src http://Ubuntu.srt.cn/ubuntu/ natty-updates universe main multiverse restricted
其他源：
deb http://ubuntu.srt.cn/ubuntu/ lucid main restricted universe multiverse
deb http://ubuntu.srt.cn/ubuntu/ lucid-security main restricted universe multiverse
deb http://ubuntu.srt.cn/ubuntu/ lucid-updates main restricted universe multiverse
deb http://ubuntu.srt.cn/ubuntu/ lucid-proposed main restricted universe multiverse
deb http://ubuntu.srt.cn/ubuntu/ lucid-backports main restricted universe multiverse
deb-src http://ubuntu.srt.cn/ubuntu/ lucid main restricted universe multiverse
deb-src http://ubuntu.srt.cn/ubuntu/ lucid-security main restricted universe multiverse
deb-src http://ubuntu.srt.cn/ubuntu/ lucid-updates main restricted universe multiverse
deb-src http://ubuntu.srt.cn/ubuntu/ lucid-proposed main restricted universe multiverse
deb-src http://ubuntu.srt.cn/ubuntu/ lucid-backports main restricted universe multiverse
deb http://archive.canonical.com/ lucid partner
更新源方法：
1. 打开终端。单击主菜单中的“应用程序 - 附件 - 终端”。
2. 修改更新服务器列表。请在终端中执行下面的两条命令：
sudo cp /etc/apt/sources.list /etc/apt/sources.list_backup
#备份原来的软件列表，会要求输入密码
sudo gedit /etc/apt/sources.list
#用gedit打开sources.list文件
在接下来在打开的文本编辑器中，把看到的内容全部删掉，在上面Ubuntu11.04源列表里选择一组对于你来说速度最快的更新服务器列表。粘贴到你所看到的窗口中。这里推荐台湾源和网易源，更新软件的速度很快！
4. 关闭文本编辑器。
5. 更新软件包列表。执行下面的命令：
sudo apt-get update
6. 安装系统更新
打开“系统->系统管理->更新管理器”，安装更新。完成后若系统提示重新启动，请重新启动系统。