Abstract: The single gimbal control moment gyro (SGCMG) configuration of a large spacecraft is studied. First, the research object of analyzing configuration is restricted. Second, The double parallel configuration, three parallel configuration, the pyramid configuration, four ridge cone configuration ,five surface cone configuration and five ridge cone configuration are analyzed according to the main indexes of configuration analysis. The merits and shortcoming of each configuration are compared. The conclusion that the optimum configuration is five ridge cone configuration is deduced. This conclusion provides the academic foundation of selecting configuration in large spacecraft SGCMG system.