一般来说ubuntu官方的软件仓库由于服务器在国外，下载更新速度较慢，需要将软件仓库更换为国内镜像点。

1、修改源配置文件

① 先备份原来的配置文件

mv /etc/apt/sources.list /etc/apt/sources.list.bak
vim /etc/apt/sources.list

② 将国内的Ubuntu镜像点添加到配置文件

• Ubuntu 163镜像点：

deb http://mirrors.163.com/ubuntu/ precise main restricted
deb-src http://mirrors.163.com/ubuntu/ precise main restricted
deb http://mirrors.163.com/ubuntu/ precise-updates main restricted
deb-src http://mirrors.163.com/ubuntu/ precise-updates main restricted
deb http://mirrors.163.com/ubuntu/ precise universe
deb-src http://mirrors.163.com/ubuntu/ precise universe
deb http://mirrors.163.com/ubuntu/ precise-updates universe
deb-src http://mirrors.163.com/ubuntu/ precise-updates universe
deb http://mirrors.163.com/ubuntu/ precise multiverse
deb-src http://mirrors.163.com/ubuntu/ precise multiverse
deb http://mirrors.163.com/ubuntu/ precise-updates multiverse
deb-src http://mirrors.163.com/ubuntu/ precise-updates multiverse
deb http://mirrors.163.com/ubuntu/ precise-backports main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ precise-backports main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ precise-security main restricted
deb-src http://mirrors.163.com/ubuntu/ precise-security main restricted
deb http://mirrors.163.com/ubuntu/ precise-security universe
deb-src http://mirrors.163.com/ubuntu/ precise-security universe
deb http://mirrors.163.com/ubuntu/ precise-security multiverse
deb-src http://mirrors.163.com/ubuntu/ precise-security multiverse
deb http://extras.ubuntu.com/ubuntu precise main
deb-src http://extras.ubuntu.com/ubuntu precise main

• 北京理工大学Ubuntu镜像点：

  deb http://mirror.bjtu.edu.cn/ubuntu/ precise main multiverse restricted universe
  deb http://mirror.bjtu.edu.cn/ubuntu/ precise-backports main multiverse restricted universe
  deb http://mirror.bjtu.edu.cn/ubuntu/ precise-proposed main multiverse restricted universe
  deb http://mirror.bjtu.edu.cn/ubuntu/ precise-security main multiverse restricted universe
  deb http://mirror.bjtu.edu.cn/ubuntu/ precise-updates main multiverse restricted universe
  deb-src http://mirror.bjtu.edu.cn/ubuntu/ precise main multiverse restricted universe
  deb-src http://mirror.bjtu.edu.cn/ubuntu/ precise-backports main multiverse restricted universe
  deb-src http://mirror.bjtu.edu.cn/ubuntu/ precise-proposed main multiverse restricted universe
  deb-src http://mirror.bjtu.edu.cn/ubuntu/ precise-security main multiverse restricted universe
  deb-src http://mirror.bjtu.edu.cn/ubuntu/ precise-updates main multiverse restricted universe

  2、更新源

apt-get update

现在修改后的国内的ubuntu镜像点就可以使用了。