A method of managing a user database in a mobile terminal includes, when communication using an arbitrary telephone number registered in a phone book occurs, updating a communication time of the telephone number to the time when the communication is terminated; searching for the communication time by a display request of phone book information including the telephone number; calculating a time interval from a present time to the communication time and searching for a connection period to which the calculated time interval belongs among a plurality of connection periods having different predetermined time intervals; and displaying a communication time mark corresponding to the searched connection period among a plurality of communication time marks corresponding to the plurality of connection periods with the requested phone book information.