For the issue that the Wireless Sensor Networks(WSNs)are vulnerable to various attacks, a WSN Intrusion Detection System(IDS)which fuses Markov Decision Process(MDP)and game theory is proposed and named as Markov Game IDS(MG-IDS). MG-IDS determines the optimal defense strategy by using game theory and the anormaly, misuse detection technology of MDP. In the meantime, it forecasts the future attack model on the basis of attack records by using MDP and attack-pattern-mining algorithm. The experimental results...