In order to improve the system performance, the cooperative diversity technology only needs a few changes in system hardware which has been adopted to obtain the diversity gains in mobile satellite communication system. First, the feasibility of cooperative diversity in mobile satellite communication system was analyzed. Second, a simple model of cooperative diversity in mobile satellite communication was presented, then the cooperative diversity in mobile satellite communication system, multi-satellites receive diversity in the Globalstar system and the MIMO in mobile satellite communication system were analyzed and compared. Last, a brief summary and future research plan was concerned.