To improve the measuring accuracy of intrusion detection, a system design of a node for intrusion detection is proposed in this paper. First, the technology that applies the traditional intrusion detection method, such as anomaly detection and misuse detection, into P2P networks is presented. Next, to build the trust relationship among the nodes, and realize the cooperation mechanism of data detection, collection and response among the nodes of P2P networks, the corresponding solving plans, such as topological structure, trust model, information share and information fusion, are proposed in this paper. Then the concept of network telescope is presented to broaden the field of vision of malicious attacks and abnormal network packets in the propagation path. Finally, a system design of a node for intrusion detection using the honeypot technology is proposed in this paper