### 修改源命令：
sudo vi /etc/apt/source.list
### 把source.list内容替换成下面其中一个源
##阿里云 deb http://mirrors.aliyun.com/ubuntu/ zesty main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ zesty-security main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ zesty-updates main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ zesty-backports main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ zesty-proposed main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ zesty main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ zesty-security main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ zesty-updates main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ zesty-backports main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ zesty-proposed main restricted universe multiverse deb http://archive.canonical.com/ubuntu/ zesty partner deb http://extras.ubuntu.com/ubuntu/ zesty main
##Ubuntu官方中国 deb http://cn.archive.ubuntu.com/ubuntu/ zesty main restricted universe multiverse deb http://cn.archive.ubuntu.com/ubuntu/ zesty-security main restricted universe multiverse deb http://cn.archive.ubuntu.com/ubuntu/ zesty-updates main restricted universe multiverse deb http://cn.archive.ubuntu.com/ubuntu/ zesty-backports main restricted universe multiverse deb http://cn.archive.ubuntu.com/ubuntu/ zesty-proposed main restricted universe multiverse deb-src http://cn.archive.ubuntu.com/ubuntu/ zesty main restricted universe multiverse deb-src http://cn.archive.ubuntu.com/ubuntu/ zesty-security main restricted universe multiverse deb-src http://cn.archive.ubuntu.com/ubuntu/ zesty-updates main restricted universe multiverse deb-src http://cn.archive.ubuntu.com/ubuntu/ zesty-backports main restricted universe multiverse deb-src http://cn.archive.ubuntu.com/ubuntu/ zesty-proposed main restricted universe multiverse deb http://archive.canonical.com/ubuntu/ zesty partner deb http://extras.ubuntu.com/ubuntu/ zesty main
##网易源 deb http://mirrors.163.com/ubuntu/ zesty main restricted universe multiverse deb http://mirrors.163.com/ubuntu/ zesty-security main restricted universe multiverse deb http://mirrors.163.com/ubuntu/ zesty-updates main restricted universe multiverse deb http://mirrors.163.com/ubuntu/ zesty-backports main restricted universe multiverse deb http://mirrors.163.com/ubuntu/ zesty-proposed main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ zesty main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ zesty-security main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ zesty-updates main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ zesty-backports main restricted universe multiverse deb-src http://mirrors.163.com/ubuntu/ zesty-proposed main restricted universe multiverse deb http://archive.canonical.com/ubuntu/ zesty partner deb http://extras.ubuntu.com/ubuntu/ zesty main
第二种方法直接在界面打开：
再进入software&updates：
选择自己所需要的源，
过程完成，说明更新完成。
