1 Backing up the system configuration
sudo cp/etc/apt/sources.list/etc/apt/source.list.bak
2 Editing the configuration
sudo vi/etc/apt/sources.list
Modify the content as follows
# Default Annotated source image to improve apt update speed, if necessary, can self-uncomment deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/xenial main restricted universe multiverse# DEB-SRC https://mirrors.tuna.tsinghua.edu.cn/ubuntu/xenial main restricted universe multiverseDeb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/xenial-updates main restricted universe multiverse# DEB-SRC https://mirrors.tuna.tsinghua.edu.cn/ubuntu/xenial-updates main restricted universe multiverseDeb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/xenial-backports main restricted universe multiverse# DEB-SRC https://mirrors.tuna.tsinghua.edu.cn/ubuntu/xenial-backports main restricted universe multiverseDeb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/xenial-security main restricted universe multiverse# DEB-SRC https://mirrors.tuna.tsinghua.edu.cn/ubuntu/xenial-security main restricted universe multiverse# Pre-release software source, not recommended to enable # Deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/xenial-proposed main restricted universe multiverse# DEB-SRC https://mirrors.tuna.tsinghua.edu.cn/ubuntu/xenial-proposed main restricted universe multiverse
Save and update after modifying
sudo apt-get update
Ubuntu 16.04 apt-get Update using Tsinghua Mirror source