In this paper we propose a theory of matching markets approach to get the access opportunity for the unauthorized users who want to share a set of channels. Matching game of spectrum allocation which can be used in cognitive radio relay system is advocated. First, in matching game algorithm, the selection of relay is abstracted to matching market problem. Then, access opportunity can be assigned by the deferred acceptance algorithm. The algorithm balance interest among relay users and encourage them to do more contributions in order to be in exchange for more spectrum resource efficiently. The proposed scheme can reduce the termination probability and the blocking probability for heterogeneous calls, simultaneously. The results of simulation show that the proposed scheme can effectively improve the access performance of secondary users.