Node discovery method for P2P (peer to peer) systems

The invention discloses a node discovery method for P2P (peer to peer) systems and relates to the technical field of broadcasting application devices and methods directly related to broadcast information or broadcast time and space. According to the method, when a user joins a network for the first time, a content route server transmits a domain name of a user domain to the user according to mapping rules of a deployment domain, the content route server returns a Tracker server address list of a user node domain or an adjacent domain to the user according to the mapping rules, when the user visits a Tracker server, the Tracker server searches a respective buffer area according to the domain name of the user to look up an autonomous domain locating in the same autonomous domain with the user node or adjacent to the user node, and the tracker server selects a certain amount of nodes from the found autonomous domain to form a neighbor node returned to the user. The method has the advantages that network downloading speed is increased, video-on-demand system delay is low and transmission quality of streaming media is guaranteed.