Abstract: In order to find a solution for the multi-tab anti-collision problem, an in-depth analysis is made of the most commonly-used framed slotted ALOHA anti-collision algorithm. A comparison is made and finds the algorithm has its advan- tages and disadvantages. An improved algorithm, by means of grouping the response tags and restricting the number of them and dynamically adjusting the frame length, is proposed. The simulation result shows that the system efficiency of the im- proved algorithm outperforms that of the framed slotted ALOHA. No matter how many tags there are in the field, it can a- chieve the optimal system efficiency.