Multicast routing is a critical problem in the P2P network. The main task for multicast routing is to establish a multicast tree with good performance, to satisfy the various qualities of service requirements, such as improving the streaming media service quality, and the utilization rate of cyber source. Many efficient overlay multicast routing algorithms are proposed to face the new challenge in current P2P network. This paper attempts to survey the current problems, the solutions for overlay multicast routing algorithms, and points out the further research directions.