A new type of energy-saving life testing device used for overrunning clutch, with simple structure, symmetrical layout and low energy consumption, is proposed to simplify the testing system and solve the problems of complexity, bulkiness and high cost, which exist in the traditional comprehensive testing systems. The interaction between two groups of the inverse cam mechanism are utilized to automatically achieve the state transition of overrunning clutch, the torsion springs to load overrunning clutch, and a flywheel to reduce speed fluctuations. Therefore the complex control system and data acquisition system are not required. The functions of the device are illustrated and verified with a 3D model of the device and its kinematics and dynamic simulation.