Abstract: The players under the repeated Prisoners’ Dilemma have the possibility of mutual cooperation．On this basis,We examined a class of two-state reputation mechanisms,and found that only three reputation mechanisms are efficient robust perfect Nash equilibrium in Markov strategies．The research shows that the strategy to cooperate with good opponents and defect against bad opponents is a global attractor,and hence cooperation is successfully achieved and sustained in the long run．

Key words: Reputation mechanisms,Repeated prisoners’ dilemma,Robust perfect Nash equilibrium