Being suitable to instant communication area, the method for security protecting user information includes steps: (1) receiving control message sent from user; the control message includes user's ID code for instant communication, ID code of mobile communication, and request for deleting user information; (2) determining whether it is bound between instant communication ID code and ID code of mobile communication; if yes, then executing step (3); otherwise, ending; (3) deleting user information stored in database corresponding to instant communication ID code. If user's ID code for instant communication is embezzled, the invention deletes user's records stored on instant communication server so as to prevent user information from leaking out. Moreover, the user information can be transferred to backup mail box pointed by user for convenient communication further.