Abstract: The present application discloses a system and a method for tag estimation and anti-collision in an RFID system, which can estimate an exact number of tags within an RF area and can rapidly identify tags by using the estimated number of tags in an RFID system. The system includes an RFID reader and RFID tags. The RFID reader includes an identification means, a collision management means, a tag number estimation means, and a reader control means. The RFID tag includes a tag communication means, a message reading means, a counter management means, an information storage means, and a tag control means. The disclosed system and method can prevent occurrence of too many idle times slots in the DFSA and too many initial collisions in the binary tree scheme, and thus can identify a large number of tags at a high speed with a small number of time slots.