The existing P2P network service discovery lack of service quality assurance consideration, and can not fully utilize the network of some node powerful service quality attributes , in order to improve the efficiency of P2P networks service discovery,this paper proposes a P2P service discovery based on QoS algorithm model by combining QoS attributes and P2P characteristics. It defines P2P service description of based on QoS and introduces semantic information into service description to improve accuracy of service matching by using these service description. On this basis, it builds up P2P service discovery model of QoS guarantee and provides genetic algorithm on P2P service discovery. At last, analysis the feasibility and effectiveness of the service discovery algorithm through the proof.