将文件里的内容全部删除，当然之前也可以用 sudo cp /etc/apt/sources.list /etc/apt/sources.list.bak命令的方式进行备份，以备不时之需。然后将下列的内容粘贴进gedit后保存即可。
Ubuntu 10.04源列表：
台湾
代码:
deb http://tw.archive.ubuntu.com/ubuntu/ lucid main universe restricted multiverse deb-src http://tw.archive.ubuntu.com/ubuntu/ lucid main universe restricted multiverse deb http://tw.archive.ubuntu.com/ubuntu/ lucid-security universe main multiverse restricted deb-src http://tw.archive.ubuntu.com/ubuntu/ lucid-security universe main multiverse restricted deb http://tw.archive.ubuntu.com/ubuntu/ lucid-updates universe main multiverse restricted deb-src http://tw.archive.ubuntu.com/ubuntu/ lucid-updates universe main multiverse restricted
SRT Sources 代码:
deb http://ubuntu.srt.cn/ubuntu/ lucid main restricted universe multiverse deb http://ubuntu.srt.cn/ubuntu/ lucid-security main restricted universe multiverse deb http://ubuntu.srt.cn/ubuntu/ lucid-updates main restricted universe multiverse deb http://ubuntu.srt.cn/ubuntu/ lucid-proposed main restricted universe multiverse deb http://ubuntu.srt.cn/ubuntu/ lucid-backports main restricted universe multiverse deb-src http://ubuntu.srt.cn/ubuntu/ lucid main restricted universe multiverse deb-src http://ubuntu.srt.cn/ubuntu/ lucid-security main restricted universe multiverse deb-src http://ubuntu.srt.cn/ubuntu/ lucid-updates main restricted universe multiverse deb-src http://ubuntu.srt.cn/ubuntu/ lucid-proposed main restricted universe multiverse deb-src http://ubuntu.srt.cn/ubuntu/ lucid-backports main restricted universe multiverse
网易（速度很快） 代码:
deb http://mirrors.163.com/ubuntu/ lucid main universe restricted multiverse deb-src http://mirrors.163.com/ubuntu/ lucid main universe restricted multiverse deb http://mirrors.163.com/ubuntu/ lucid-security universe main multiverse restricted deb-src http://mirrors.163.com/ubuntu/ lucid-security universe main multiverse restricted deb http://mirrors.163.com/ubuntu/ lucid-updates universe main multiverse restricted deb http://mirrors.163.com/ubuntu/ lucid-proposed universe main multiverse restricted deb-src http://mirrors.163.com/ubuntu/ lucid-proposed universe main multiverse restricted deb http://mirrors.163.com/ubuntu/ lucid-backports universe main multiverse restricted deb-src http://mirrors.163.com/ubuntu/ lucid-backports universe main multiverse restricted deb-src http://mirrors.163.com/ubuntu/ lucid-updates universe main multiverse restricted
ubuntu官方上海源，提供 Kernel，Hiweed，ubuntu 代码:
deb http://mirror.rootguide.org/ubuntu/ lucid main universe restricted multiverse deb-src http://mirror.rootguide.org/ubuntu/ lucid main universe restricted multiverse deb http://mirror.rootguide.org/ubuntu/ lucid-security universe main multiverse restricted deb-src http://mirror.rootguide.org/ubuntu/ lucid-security universe main multiverse restricted deb http://mirror.rootguide.org/ubuntu/ lucid-updates universe main multiverse restricted deb http://mirror.rootguide.org/ubuntu/ lucid-proposed universe main multiverse restricted deb-src http://mirror.rootguide.org/ubuntu/ lucid-proposed universe main multiverse restricted deb http://mirror.rootguide.org/ubuntu/ lucid-backports universe main multiverse restricted deb-src http://mirror.rootguide.org/ubuntu/ lucid-backports universe main multiverse restricted deb-src http://mirror.rootguide.org/ubuntu/ lucid-updates universe main multiverse restricted
搜狐 代码:
deb http://mirrors.shlug.org/ubuntu/ lucid main universe restricted multiverse deb-src http://mirrors.shlug.org/ubuntu/ lucid main universe restricted multiverse deb http://mirrors.shlug.org/ubuntu/ lucid-security universe main multiverse restricted deb-src http://mirrors.shlug.org/ubuntu/ lucid-security universe main multiverse restricted deb http://mirrors.shlug.org/ubuntu/ lucid-updates universe main multiverse restricted deb http://mirrors.shlug.org/ubuntu/ lucid-proposed universe main multiverse restricted deb-src http://mirrors.shlug.org/ubuntu/ lucid-proposed universe main multiverse restricted deb http://mirrors.shlug.org/ubuntu/ lucid-backports universe main multiverse restricted deb-src http://mirrors.shlug.org/ubuntu/ lucid-backports universe main multiverse restricted deb-src http://mirrors.shlug.org/ubuntu/ lucid-updates universe main multiverse restricted
骨头源，骨头源是bones7456架设的一个Ubuntu源 ，提供ubuntu,deepin 代码:
deb http://ubuntu.srt.cn/ubuntu/ lucid main universe restricted multiverse
deb-src http://ubuntu.srt.cn/ubuntu/ lucid main universe restricted multiverse deb http://ubuntu.srt.cn/ubuntu/ lucid-security universe main multiverse restricted deb-src http://ubuntu.srt.cn/ubuntu/ lucid-security universe main multiverse restricted deb http://ubuntu.srt.cn/ubuntu/ lucid-updates universe main multiverse restricted deb http://ubuntu.srt.cn/ubuntu/ lucid-proposed universe main multiverse restricted deb-src http://ubuntu.srt.cn/ubuntu/ lucid-proposed universe main multiverse restricted deb http://ubuntu.srt.cn/ubuntu/ lucid-backports universe main multiverse restricted deb-src http://ubuntu.srt.cn/ubuntu/ lucid-backports universe main multiverse restricted deb-src http://ubuntu.srt.cn/ubuntu/ lucid-updates universe main multiverse restricted保存后输入下面的指令刷新源信息：
#sudo apt-get update
然后输入：
#sudo apt-get upgrade
就可以进行系统升级了。