The invention proposes a method of peer-to-peer instant messaging and the mobile terminal thereof, which could make the mobile terminal to establish and maintain a list of friend users and update the connection status of the friend users timely. The method of peer-to-peer instant messaging includes following steps: receiving the list of on-line users with capability of peer-to-peer instant messaging sent by the radio network (S260); comparing said list of particular users with said received list of on-line users (S270); updating, according to said comparison result, the connection status record of each user in said list of particular users (S280) so that the mobile terminal could establish a peer-to-peer instant messaging with at least one user mobile terminal in said list of particular users according to said updated connection status record. The present invention enables the user to establish peer-to-peer connection more effectively and to perform instant messaging while occupying less network resources.