Clamping force control of metal V-belt type CVT(Continuously Variable Transmission) is one of the key technologies. Because of the complexity of the metal V-belt transmission, it is hard to use mathematical model to accurately describe the clamping force formula. Large numbers of tests should be done, and then parameters should be modified on the basis of an empirical model. A clamping force test device was built, on which the clamping force relationship between the primary cylinder pressure and the slave cylinder pressure was calibrated at a steady state, and the critical clamping force was defined. The CVT efficiency was also tested. In order to judge the reasonableness of the clamping force, a clamping force test was done on a test vehicle equipped with RDC15 CVT made in China. The results have shown that the CVT Transmission meet the requirements after the clamping force calibration. Technological support will be provided for the mass production of CVT in China.