This paper addresses the problem of service composition in military organization cloud cooperation(MOCC). Military service providers(MSP) cooperate together to provide military resources for military service users(MSU). A group of atom services, each of which has its level of quality of service(QoS), can be combined together into a certain structure to form a composite service. Since there are a large number of atom services having the same function, the atom service is selected to participate in the composite service so as to fulfill users’ will. In this paper a method based on discrete particle swarm optimization(DPSO) is proposed to tackle this problem. The method aims at selecting atom services from service repositories to constitute the composite service, satisfying the MSU’s requirement on QoS. Since the QoS criteria include location-aware criteria and location-independent criteria, this method aims to get the composite service with the highest location-aware criteria and the best-match location-independent criteria. Simulations show that the DPSO has a better performance compared with the standard particle swarm optimization(PSO) and genetic algorithm(GA). This paper addresses the problem of service composition in military organization cloud cooperation (MOCC). Military service providers (MSP) cooperate together to provide military resources for military service users (MSU). A group of atom services, each of which has its level of quality of service (QoS), can be combined together into a certain structure to form a composite service. Since there are a large number of atom services have the same function, the atom service is selected to participate in the composite service so as to fulfill users’ will. In this paper a method based on discrete particle swarm optimization (DPSO) is proposed to tackle this problem. The method aims at selecting atom services from service repositories to constitute the composite service, satisfying the MSU’s requirement on QoS. Since the QoS criteria include location-aware criteria and location-independent criteria, this method aims to get the composite service with the highest location-aware criteria and the bes t-match location-independent criteria. Simulations show that the DPSO has a better performance compared with the standard particle swarm optimization (PSO) and genetic algorithm (GA).