The invention provides a node in P2P stream media and a method for optimizing a neighbor node table of the node. The method comprises recoding historical online status information of a first node, historical online status information of all correlative nodes, and network delay information and transmission bandwidth information between all the nodes and the first node by using the first node; obtaining all information recorded in the last step when the first node is online and calculating comprehensive availability values between the first node and all the correlative nodes in order to obtain a comprehensive availability value sequence; selecting large-value [gamma] nodes from the sequence as optimum neighbor nodes of the first nodes; replacing current neighbor nodes in the neighbor node table of the first node with the optimum neighbor nodes, wherein the first node is any node in a P2P network, the correlative nodes are a plurality of historical neighbor nodes with relatively high comprehensive availability during the time quantum between the time when the first node is online at the first time and current time, and current neighbor nodes stored in the neighbor node table at the current online time of the first node.