The anti collision algorithm determines the operating efficiency of RFID systems. An improved hybrid query tree (IHQT) anticollision algorithm is presented in this paper, which is based on the query tree algorithm. When collision occurs, the collided node will split into some child nodes. IHQT addes a branch prediction stage before the reader query collided tags to avoid the idle slots. The branch prediction method presented in this paper can predict the location of idle slots accurately. When the reader generates new query prefixes, those query prefixes which visit the idle slots will be avoided successfully. The performance analysis of algorithm and simulation results show that under the premise of a small increase even significant decrease in the query times of reader, the number of timeslots and throughput of IHQT algorithm are significantly better than the existing query tree anticollision algorithms.