准备工作

确认系统版本

cat /etc/issue

Stretch jessie wheezy 分别对应Debian9 Debian8 Debian7版本。
可以在源地址对应修改，以下按Debian9进行。

更名备份源文件

cd /etc/apt/
mv sources.list sources.listbak

编辑源文件

vim /etc/apt/sources.list

写入源地址

阿里云源

deb http://mirrors.aliyun.com/debian stretch main contrib non-free
deb-src http://mirrors.aliyun.com/debian stretch main contrib non-free
deb http://mirrors.aliyun.com/debian stretch-updates main contrib non-free
deb-src http://mirrors.aliyun.com/debian stretch-updates main contrib non-free
deb http://mirrors.aliyun.com/debian-security stretch/updates main contrib non-free
deb-src http://mirrors.aliyun.com/debian-security stretch/updates main contrib non-free

网易163源

deb http://mirrors.163.com/debian/ stretch main non-free contrib 
deb http://mirrors.163.com/debian/ stretch-updates main non-free contrib 
deb http://mirrors.163.com/debian/ stretch-backports main non-free contrib 
deb-src http://mirrors.163.com/debian/ stretch main non-free contrib 
deb-src http://mirrors.163.com/debian/ stretch-updates main non-free contrib 
deb-src http://mirrors.163.com/debian/ stretch-backports main non-free contrib 
deb http://mirrors.163.com/debian-security/ stretch/updates main non-free contrib 
deb-src http://mirrors.163.com/debian-security/ stretch/updates main non-free contrib

清华大学源

deb https://mirrors.tuna.tsinghua.edu.cn/debian/ stretch main non-free contrib 
deb https://mirrors.tuna.tsinghua.edu.cn/debian/ stretch-updates main non-free contrib 
deb https://mirrors.tuna.tsinghua.edu.cn/debian/ stretch-backports main non-free contrib 
deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ stretch main non-free contrib 
deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ stretch-updates main non-free contrib 
deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ stretch-backports main non-free contrib 
deb https://mirrors.tuna.tsinghua.edu.cn/debian-security/ stretch/updates main non-free contrib 
deb-src https://mirrors.tuna.tsinghua.edu.cn/debian-security/ stretch/updates main non-free contrib

同步到本地

apt-get update

搞定.