Abstract: In the application of radio frequency system, readers can quickly and accurately identify conflicts and identify tags and get information, which is an important way to improve system performance in the presence of multiple tags. In order to solve the conflict problem in the process of tag identification, an improved algorithm is proposed based on the dynamic frame time slot ALOHA algorithm and by using the extension of the birthday paradox probability theory. Through the algorithm simulation, the algorithm can effectively improve the accuracy of tag identification, reduce the time in the process of identification, so as to improve the efficiency of the radio frequency system, improve the performance of the system.