Abstract: In order to meet the inertia configuration requirements of a certain type of aviation inertial test-bed, a new type of flywheel combination system is designed. The bearing is installed inside the selection flywheel, which reduces the number of bearing houses. The pin shaft is used to engage and separate the selection flywheel from the main flywheel, which is easy to install and operate. Compared with the fork clutch mechanism, the system effectively reduces the axial space size of the flywheel combination system, the shaft structure is simple, the processing accuracy is low, and the economy is good.