On count of the rapid decline of efficiency when more tags were in radio frequency identification system,it used the Hamming weight of tags ID top M bits to group the tags which were in the scope of the reader,this paper proposed a dynamic framed slotted ALOHA algorithm based on Hamming weight grouping( LGDFSA). And it simulated the algorithm by MATLAB. It compared with dynamic framed slotted ALOHA algorithm,the results show the system throughput is improved and tends to be stable,it cuts down the total num...