User search method, system, server and client terminal for instant communication

The embodiment of the invention discloses an instant communication IM user searching method, comprising the steps of: after IM server receives TAG attribute protocol instruction carrying a tag of TAG attribute and target user identity ID, if the user sending the protocol instruction is the target user, or the user has good friend relationship with the target user, recording the ID of the target user in the user ID list having the TAG attribute, and recording the TAG attribute in the user information of the target user; after IM server receives searching protocol instruction carrying the TAG attribute, if the IM server searches record of the TAG attribute, determining user having the TAG attribute, and sending information of the determined user to IM client of the searching protocol instruction. The invention also discloses an IM system, a server and a client for supporting TAG search. The embodiment of the invention can be applied to searching IM user for with user's own true situation reaction.