Environment: Linux CentOS 7
1. Enter the sshd configuration file: vi /etc/ssh/sshd_config
2. Find the line "#Port 22", delete the comment character #, and change the port to (the port number you want to change, such as: 2022): 
3. Restart the sshd service:
systemctl restart sshd
The following error messages may appear:
Job for sshd.service failed because the control process exited with error code.See "systemctI status sshd.service" and "journalctI -xe" for details.
The reason is that SELinux (a security subsystem of Linux) rejected the restart. Just temporarily turn the SELinux firewall off:
setenforce 0
Then use the "systemctl restart sshd" command to restart the service and check whether the port is enabled:
netstat -atunlp|grep sshd
It can be found that the port has been opened: 
4. Finally, the firewall allows port 2022:
firewall-cmd --zone=public --add-port="2022"/tcp --permanent
Reload the firewall when done:
firewall-cmd --reload
After the prompt is successful, you can access the server through port 2022.