1、原文件备份

sudo cp /etc/apt/sources.list /etc/apt/sources.list.bak

2、编辑源列表文件

sudo vim /etc/apt/sources.list

3、将原来的列表删除，添加如下内容（中科大镜像源-其他源请自行查找）

deb http://www.landui.com/ubuntu/ xenial main restricted universe multiverse

deb http://www.landui.com/ubuntu/ xenial-security main restricted universe multiverse

deb http://www.landui.com/ubuntu/ xenial-updates main restricted universe multiverse

deb http://www.landui.com/ubuntu/ xenial-proposed main restricted universe multiverse

deb http://www.landui.com/ubuntu/ xenial-backports main restricted universe multiverse

deb-src http://www.landui.com/ubuntu/ xenial main restricted universe multiverse

deb-src http://www.landui.com/ubuntu/ xenial-security main restricted universe multiverse

deb-src http://www.landui.com/ubuntu/ xenial-updates main restricted universe multiverse

deb-src http://www.landui.com/ubuntu/ xenial-proposed main restricted universe multiverse

deb-src http://www.landui.com/ubuntu/ xenial-backports main restricted universe multiverse

4、运行sudo apt-get update