The EPC C1 Gen2 (Electronic Product Code Class 1 Generation 2) standard uses the traditional Q-algorithm to solve the tag anti-collision problem. The interrogator needs to frequently send QueryAdjust command to adjust the frame length when multiple tags or no tags synchronously response to the interrogator in a time slot, so that the system will consume a lot of energy, and the system throughput is also very low. According to these deficiencies, this paper proposes a fast and stable algorithm, named FSQ algorithm, by dynamically adjusting Q value to lower the frequency of interrogator sending QueryAdjust command, and through optimizing the time slots, the simulation results indicate FSQ algorithm outperforms the traditional Q-algorithm and the system power consumption has been got greatly lowered.