Scalable video representation of the state-of-art scalable extension of the H.264/MPEG-4 AVC (SVC) and its combined 3d scalability feature offer an excellent solution to flexible video multicast over IP network. In order to relieve the impact of the severe bandwidth fluctuations and packet loss to the reconstructed quality in heterogeneous networks like the internet, a GOP-adaptive layer-based priority ordering algorithm for SVC is proposed in this paper. The method ordered the SVC bit stream according to the rate distortion contribution of different layer to the whole performance within a GOP, which makes the transmission more efficient and robust under the same bandwidth condition. Simulation results of different sequences are given to demonstrate that the proposed algorithms offer better performance in video quality as compared the default SVC ordering method and the SNR-based ordering method.