方法有很多种，先说解决了我燃眉之急的。
方法一:
找到.gitconfig，添加如下配置。(或者用git config --global命令)
[core]
packedGitLimit = 512m
packedGitWindowSize = 512m
[pack]
deltaCacheSize = 2047m
packSizeLimit = 2047m
windowMemory = 2047m方法二：
网上看到做多的，
git config --global core.compression 0方法三:（stackoverflow上面看到的高分解答）
First, turn off compression:
git config --global core.compression 0
Next, let's do a partial clone to truncate the amount of info coming down:
git clone --depth 1 <repo_URI>
When that works, go into the new directory and retrieve the rest of the clone:
git fetch --unshallow
or, alternately,
git fetch --depth=2147483647
Now, do a regular pull:
git pull --all
I think there is a glitch with msysgit in the 1.8.x versions that exacerbates these symptoms, so another option is to try with an earlier version of git (<= 1.8.3, I think).
这一套三板斧下来，应该可以解决80%人的问题了。