前言
Ubuntu默认的安装源是http://archive.ubuntu.com/ubuntu/，在国内访问速度比较慢。最好是换成国内的安装源，能够节省很多时间。本文中，我们假设系统为Ubuntu14.04.5，打算换成Ubuntu官方中国的安装源（阿里、网易、搜狐等的更换方法类似）。Ubuntu14的源地址可以在模板:14.04source中找到，其他版本Ubuntu的源地址可以在源列表中找到。
配置步骤
配置步骤参考如何修改Ubuntu的源列表(source list)，操作如下：
1、备份源列表文件
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
修改为：
deb http://cn.archive.ubuntu.com/ubuntu/ trusty main restricted universe multiverse
deb http://cn.archive.ubuntu.com/ubuntu/ trusty-security main restricted universe multiverse
deb http://cn.archive.ubuntu.com/ubuntu/ trusty-updates main restricted universe multiverse
deb http://cn.archive.ubuntu.com/ubuntu/ trusty-backports main restricted universe multiverse
##測試版源
deb http://cn.archive.ubuntu.com/ubuntu/ trusty-proposed main restricted universe multiverse
# 源碼
deb-src http://cn.archive.ubuntu.com/ubuntu/ trusty main restricted universe multiverse
deb-src http://cn.archive.ubuntu.com/ubuntu/ trusty-security main restricted universe multiverse
deb-src http://cn.archive.ubuntu.com/ubuntu/ trusty-updates main restricted universe multiverse
deb-src http://cn.archive.ubuntu.com/ubuntu/ trusty-backports main restricted universe multiverse
##測試版源
deb-src http://cn.archive.ubuntu.com/ubuntu/ trusty-proposed main restricted universe multiverse
# Canonical 合作夥伴和附加
# deb http://archive.canonical.com/ubuntu/ trusty partner
# deb http://extras.ubuntu.com/ubuntu/ trusty main
3、更新资源包
sudo apt-get update
如果报错Error connecting: Could not connect: Connection refused ，那么可以参考“Unable to connect” error with apt-get?和apt-get update Error connecting Could not connect Connection refused。
4、更新软件
sudo apt-get upgrade
