The bearing of wind turbine includes yaw bearing,pitch bearing and main bearing,which are the key components of wind turbine.The factory clearance,friction torque and no-load temperature rise of wind turbine bearing are important indexes that affect its operation performance.Accurate measurement of bearing clearance,friction torque and no-load temperature rise can quantitatively analyze the consistency of bearing design and manufacture,and ensure the reliability of subsequent installation.A special wind turbine bearing function test system was designed to test the factory clearance,friction torque and no-load temperature rise of the wind turbine bearing，and verified the reliability of design and manufacture of the wind turbine bearing.