Abstract: Intrusion tolerance is a new mechanism used to build secure computer networks. Therefore, its very important to analyze and evaluate the security performance of intrusion tolerant networks before intrusion tolerance is absolutely adopted. Thus, a security analysis model of intrusion tolerant systems based on game theory is proposed in this paper. According to the analysis model, the processes between attacking and tolerating intrusions are considered as a two-player zero-sum stochastic game, in which the optimal action strategies and expected payoffs of the two parties are studied. By using the study results, this paper analyzes the availability, confidentiality and integrality of intrusion-tolerance systems from the perspective of mean time to failure. Meanwhile, it analyzes the factors that will affect the attackers choices about action strategies, and obtains the relationships between attack will, payoff and action strategy. The results present the underlying interconnections between intrusion tolerant systems and attackers, which will provide helpful references to withstand the network attacks and intrusions.