The latest release can be directly downloaded from debian site. This doc is intended for downloading archived CD image (aka old, non-release versions).

Install Jigdo

sudo apt-get install jigdo-file

After installation, there will be 3 commands available: jigdo-file, jigdo-lite, and jigdo-mirror.

jigdo-lite is used for our purpose. jigdo-file is used to generate jigdo file from cd image.

Download template and jigdo file

For example, debian 7.9 CD1

http://cdimage.debian.org/cdimage/archive/7.9.0/i386/jigdo-cd/

Download both debian-7.9.0-i386-CD-1.jigdo and debian-7.9.0-i386-CD-1.template files and put them into the same folder.

wget http://cdimage.debian.org/cdimage/archive/7.9.0/i386/jigdo-cd/debian-7.9.0-i386-CD-1.jigdo
wget http://cdimage.debian.org/cdimage/archive/7.9.0/i386/jigdo-cd/debian-7.9.0-i386-CD-1.template

Open a terminal and cd into this folder, do

jigdo-lite debian-7.9.0-i386-CD-1.jigdo

press ENTER to bypass file scan.

input the following link when being asked for a mirror link.

http://ftp.cn.debian.org/debian/