Anti-worm is an effective way to fight against malicious worm and has been followed closely by malicious worm researchers recently.However,active and passive confronting technologies in peer-to-peer (P2P) networks have not been studied in depth.This paper introduces both of them to fight against malicious worm in P2P networks.To study their effectiveness in P2P networks,this paper takes the topology degree in P2P networks into consideration and puts forward a four-state propagation model for active anti-worm and a five-state propagation model for passive anti-worm respectively.Both of the models are simplified in the case that size of a P2P network is large enough.The simulation results have not only validated the effectiveness of our propagation models but also evaluated the excellent performance of both active anti-worm and passive anti-worm.