In the Cognitive Radio(CR) network, the opportunistic spectrum sensing and access is of paramount importance to the primary user’s capacity. This paper propose a multi-user Decentralized Partially Observable Markov Decision Process(Dec-POMDP) CR spectrum access algorithm. In this framework, adjacent CR users exchange access policies with neighbors, and according to policy gradient, each local CR user adjusts its own access policy till the system of CR network obtains an optimum joint access policy. Simulation results show that this algorithm can lower the capacity loss of authorized user efficiently and improve spare spectrum efficiency, moreover, it can make access decision more efficiently.