1、进入root模式

su root

2、备份sources.list

cp /etc/apt/sources.list /etc/apt/sources.list_backup

3、更改源为国内阿里云源

vi /etc/apt/sources.list
# Aliyun
deb-src http://archive.ubuntu.com/ubuntu bionic main restricted #Added by software-properties
deb http://mirrors.aliyun.com/ubuntu/ bionic main restricted
deb-src http://mirrors.aliyun.com/ubuntu/ bionic main restricted multiverse universe #Added by software-properties
deb http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted multiverse universe #Added by software-properties
deb http://mirrors.aliyun.com/ubuntu/ bionic universe
deb http://mirrors.aliyun.com/ubuntu/ bionic-updates universe
deb http://mirrors.aliyun.com/ubuntu/ bionic multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-updates multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse #Added by software-properties
deb http://archive.canonical.com/ubuntu bionic partner
deb-src http://archive.canonical.com/ubuntu bionic partner
deb http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted multiverse universe #Added by software-properties
deb http://mirrors.aliyun.com/ubuntu/ bionic-security universe
deb http://mirrors.aliyun.com/ubuntu/ bionic-security multiverse