Abstract: To motivate nodes to forward packets in Ad hoc networks under the condition of imperfect information, repeated game is often used to model the process of sequential interactions between nodes and the Bellman equations is applied to design strategy based on sequential equilibrium. The nodes need not to exchange their monitor information, so it saves nodes energy and reduces the network burden. Compared with existing sequential equilibrium strategy, since the proposed strategy does not use trigger mechanism, which is sensible to observation error, it improves the cooperation rate and the average benefits of networks with imperfect information. Simulation compares the performance of two sequential equilibrium strategies. The results indicate that the proposed strategy not only improves the cooperation rate, but also has a good adaptability.