In P2P systems, nodes use a plenty of styles flooding the messages to the destination or discover the target node. Therefore, it is important to guarantee the efficiency and security of message routing between the source and the destination. Unfortunately, malicious attackers can easily insert a lot of nodes they controlled, and disturb the message routing between honest nodes. In order to counter such attacks, secure routing protocols which ensure successful message routing are needed. Furthermore, it is very important to analyze existing routing protocols for the inventions of secure routing protocols. In this paper, we propose a security model for evaluating security level of routing protocol. In this model, we define the concept of Regular Path, and use it as the indicator of security level. Then, we analyze three representative routing protocols based on proposed model to make comparisons from the aspects of security level and implement level. The simulation and the related theory have proven that Conditional Probability of Regular Path(CPRP) is mainly affected by the scale of network and malicious nodes rate in the network. The results can help to choose a reasonable routing protocol of the context-based application, or give some basic guideline for the invention of the new routing protocol.