Because of the strong nonNewtonian properties and thixotropic properties of greases,the test results of their lubricating performances are uncertain.In order to realize the effective test of grease performances,the motion control method of ballondisc contact greaselubricated test bench was investigated.The spindle structure with high rotation precision of the test bench was designed,the motion control method of AC servo motor based on PLC was studied,and the lubricating film thickness of grease was measured according to the light interference method.The test results show that the method can accurately control the tribopair motion of ballondisc contact greaselubricated test bench,and realize the required motion law.The test bench can measure the lubricating film thickness of grease under different conditions precisely and conveniently.