Abstract: The total security throughput of multicast group is limited by the users with the worst channel quality. Moreover, traditional the artificial noise of physical layer security techniques for unicast transmission, do not apply well to multicast transmission. To solve this problem, we consider a layered coding based physical layer secure multicast algorithm. The algorithm can max security throughput of the entire multicast group, while ensuring the security of all users' quality of service (QoS) requirements. The simulation results show that the performance gap between the optimal algorithm and the suboptimal algorithm is very small. Moreover, the computational complexity of suboptimal algorithm is obviously reduced. The proposed algorithm is much better than the conventional multicast security scheme (CMSS). In addition, it achieves more throughput than another algorithm.