Abstract: The conceptual connotation of military big data is introduced, its influences on joint operation mode, combat capability improvement are analyzed. A comparative analysis of the differences and connections between military and civilian big data in data acquisition, transmission, labeling, management, analysis and others focused on the joint operation features and typical scenarios is performed. Based on this, the challenges faced by military big data system of systems in data asset construction, shared exchange, analysis & applications and so on are analyzed, and the big data asset construction and shared exchange based on metadata technologies, and the technical routes of big data application construction based on federated learning are put forward. The data asset management and service platform, the data processing analysis and service platform are designed. It can provide guidance and reference for the development and construction of military big data system of systems.