His body will be displayed at the Kumsusan Memorial Palace alongside his father, Kim Il-sung.
There are also plans to build memorial towers for him, state media said, and his 16 February birthday will be marked as a “Day of the Shining Star”.
The news came in an announcement from state news agency KCNA.
The decision to preserve Kim Jong-il was made to show “the unanimous desire and ardent request” of the party to hold Kim Jong-il in high esteem “as the eternal leader of the party”, the KCNA report said.
The Kumsusan Memorial Palace was “eternal president” Kim Il-sung’s home before it was converted into a mausoleum after his death.
The “Shining Star” is thought to be a reference to rockets built by North Korea under Mr Kim’s policy of channelling funding to the military.