Abstract: The unstructured P2P network becomes more and more popular with the easily global deployment and supporting fuzzy key match，but the unstructured P2P network has poor scalability because of the flood broadcasting.This paper puts forward a balanced binary tree as the unstructured P2P network topology structure based on the existing problems of the unstructured P2P network topology structure，designs the corresponding algorithm of network peer insert，leave，and resources search，and shows the improved results by corresponding simulation.