用vi工具编辑文件
sudo vi /etc/apt/sources.list
以trusty(14.04)为例，插入下面内容到文件的最前面：
deb http://mirrors.163.com/ubuntu/ trusty main restricted universe multiverse deb http://mirrors.163.com/ubuntu/ trusty-security main restricted universe multiverse deb http://mirrors.163.com/ubuntu/ trusty-updates main restricted universe multiverse deb http://mirrors.163.com/ubuntu/ trusty-proposed main restricted universe multiverse deb http://mirrors.163.com/ubuntu/ trusty-backports main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ trusty main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ trusty-security main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ trusty-updates main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ trusty-proposed main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ trusty-backports main restricted universe multiverse
保存即可享受网易镜像加速。（电信线路飞快）
其他的版本，替换trusty为对应的名称即可：
lucid(10.04)
precise(12.04)
trusty(14.04)
utopic(14.10)
vivid(15.04)
wily(15.10)
参考地址：
http://mirrors.163.com/.help/ubuntu.html