With the springing up and development of broad-band network technology, such as IPV6, and 3G, etc., media streaming has become an important application of Internet. Because of the media streaming services high bandwidth requirement and long duration, providing larger scale media streaming service over the Internet is a challenging problem. In existing P2P networks, the churn caused by nodes dynamic behavior has serious effect on reliability, usability, service response speed and lifetime of P2P large-scale reliable media streaming service. Churn is one of the main problems faced by P2P large-scale reliable media streaming service. Consequently, analyzing the impact of churn on network and finding approaches for reasonable and effective inhibitory mechanisms have become pivotal research issues in this field. This paper surveys the existing theories and methods about churn. Based on the impact on network performance rendered by dynamic behavior of nodes, the paper puts forward models to measure the important indicators such as churn period, churn frequency, and churning node connections. It also presents rules and strategies to handle churn. The simulation results show that the model can effectively reduce churn, and improve the network performance and service quality for P2P reliable media streaming. Therefore, the P2P reliable media streaming network can be more stable and get sustainable serving ability.