1.sudo gedit /etc/apt/sources.list
编辑你的源列表，添加下面列表中你觉得适合你的，复制到你的列表中，然后保存列表。
成都市 电子科技大学更新服务器（教育网，推荐校园网和网通用户使用）：
deb http://ubuntu.uestc.edu.cn/ubuntu/ jaunty main multiverse restricted universe
deb http://ubuntu.uestc.edu.cn/ubuntu/ jaunty-backports main multiverse restricted universe
deb http://ubuntu.uestc.edu.cn/ubuntu/ jaunty-proposed main multiverse restricted universe
deb http://ubuntu.uestc.edu.cn/ubuntu/ jaunty-security main multiverse restricted universe
deb http://ubuntu.uestc.edu.cn/ubuntu/ jaunty-updates main multiverse restricted universe
deb-src http://ubuntu.uestc.edu.cn/ubuntu/ jaunty main multiverse restricted universe
deb-src http://ubuntu.uestc.edu.cn/ubuntu/ jaunty-backports main multiverse restricted universe
deb-src http://ubuntu.uestc.edu.cn/ubuntu/ jaunty-proposed main multiverse restricted universe
deb-src http://ubuntu.uestc.edu.cn/ubuntu/ jaunty-security main multiverse restricted universe
deb-src http://ubuntu.uestc.edu.cn/ubuntu/ jaunty-updates main multiverse restricted universe
== 如果无法解析uestc.edu.cn域名，请使用以下地址 ==
deb http://ubuntu.dormforce.net/ubuntu/ jaunty main multiverse restricted universe
deb http://ubuntu.dormforce.net/ubuntu/ jaunty-backports main multiverse restricted universe
deb http://ubuntu.dormforce.net/ubuntu/ jaunty-proposed main multiverse restricted universe
deb http://ubuntu.dormforce.net/ubuntu/ jaunty-security main multiverse restricted universe
deb http://ubuntu.dormforce.net/ubuntu/ jaunty-updates main multiverse restricted universe
deb-src http://ubuntu.dormforce.net/ubuntu/ jaunty main multiverse restricted universe
deb-src http://ubuntu.dormforce.net/ubuntu/ jaunty-backports main multiverse restricted universe
deb-src http://ubuntu.dormforce.net/ubuntu/ jaunty-proposed main multiverse restricted universe
deb-src http://ubuntu.dormforce.net/ubuntu/ jaunty-security main multiverse restricted universe
deb-src http://ubuntu.dormforce.net/ubuntu/ jaunty-updates main multiverse restricted universe
上海市上海交通大学更新服务器（教育网，推荐校园网和网通用户使用）：
deb http://ftp.sjtu.edu.cn/ubuntu/ jaunty main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ jaunty-backports main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ jaunty-proposed main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ jaunty-security main multiverse restricted universe
deb http://ftp.sjtu.edu.cn/ubuntu/ jaunty-updates main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ jaunty main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ jaunty-backports main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ jaunty-proposed main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ jaunty-security main multiverse restricted universe
deb-src http://ftp.sjtu.edu.cn/ubuntu/ jaunty-updates main multiverse restricted universe
中国科学技术大学更新服务器（教育网，推荐校园网和网通用户使用）：
deb http://debian.ustc.edu.cn/ubuntu/ jaunty main multiverse restricted universe
deb http://debian.ustc.edu.cn/ubuntu/ jaunty-backports main multiverse restricted universe
deb http://debian.ustc.edu.cn/ubuntu/ jaunty-proposed main multiverse restricted universe
deb http://debian.ustc.edu.cn/ubuntu/ jaunty-security main multiverse restricted universe
deb http://debian.ustc.edu.cn/ubuntu/ jaunty-updates main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ jaunty main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ jaunty-backports main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ jaunty-proposed main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ jaunty-security main multiverse restricted universe
deb-src http://debian.ustc.edu.cn/ubuntu/ jaunty-updates main multiverse restricted universe
中国Tai w Tai w大学更新服务器（推荐网通用户使用，电信PING平均响应速度41MS。强烈推荐此源，比较完整，较少出现同步问题）：
deb http://ubuntu.csie.ntu.edu.tw/ubuntu/ jaunty main restricted universe multiverse
deb-src http://ubuntu.csie.ntu.edu.tw/ubuntu/ jaunty main restricted universe multiverse
deb http://ubuntu.csie.ntu.edu.tw/ubuntu/ jaunty-updates main restricted universe multiverse
deb-src http://ubuntu.csie.ntu.edu.tw/ubuntu/ jaunty-updates main restricted universe multiverse
deb http://ubuntu.csie.ntu.edu.tw/ubuntu/ jaunty-backports main restricted universe multiverse
deb-src http://ubuntu.csie.ntu.edu.tw/ubuntu/ jaunty-backports main restricted universe multiverse
deb http://ubuntu.csie.ntu.edu.tw/ubuntu/ jaunty-security main restricted universe multiverse
deb-src http://ubuntu.csie.ntu.edu.tw/ubuntu/ jaunty-security main restricted universe multiverse
deb http://ubuntu.csie.ntu.edu.tw/ubuntu/ jaunty-proposed main multiverse restricted universe
deb-src http://ubuntu.csie.ntu.edu.tw/ubuntu/ jaunty-proposed main restricted universe multiverse
2.sudo apt-get update 更新源列表信息
请至少保存官方更新源。