apt source

Source:USTC

sudo vim /etc/apt/source.list

or use the command:

sudo sed -i 's/archive.ubuntu.com/mirrors.ustc.edu.cn/g' /etc/apt/sources.list

For Kali Linux:

deb https://mirrors.ustc.edu.cn/kali kali-rolling main non-free contrib
deb-src https://mirrors.ustc.edu.cn/kali kali-rolling main non-free contrib

For more information USTC Open Source

Finally:

sudo apt-get update