Tag identification time is handled as an important factor because the performance of RFID system is decided by this factor dominantly. To improve this ability, many anti-collision algorithms have been applied on RFID system. ALOHA based anti-collision algorithms are simple and they have superior anticollision ability. But, it has disadvantage that the identification performance grows worse as the collision probability increases rapidly in case the reader recognize multiple tags. The improved framed slotted ALOHA is proposed to solve this problem. The collision probability is reduced and the tag identification speed increases with the proposed method. By the result, the proposed method offers the more efficient identification rate than that of the typical ALOHA method.