In order to verify the bearing performance of the 4 MW to 5 MW wind power gearbox,a bearing testing machine was developed.The testing machine could control the bearings rotation direction,speed,axial and radial loads,and lubricating oil flow through the load spectrum to simulate the actual working conditions of the bearing,and the method of measuring the vibration and temperature of the bearing was used to laterally reflect the real-time state of the bearing.The frequency converter was used to control the variable frequency speed regulation motor to change the bearing speed and direction,the hydraulic proportional servo valve was loaded with variable and precise,the lubricating oil flow was adjusted by the lubrication proportional flow valve,the bearing temperature was measured by the platinum thermal resistance temperature sensor,the bearing vibration was measured by the acceleration sensor cooperating with the vibration acquisition module.The testing machine can complete the enhanced life test by speeding up the bearing speed and increasing the bearing load.After 50 000 min of testing,the test machine runs smoothly,has good reliability and normal data,which achieves the design purpose.