As the power unit of the wind turbine,the reliable operation of the pitch motor is the core of the normal operation of the wind turbine.Aiming at the abnormal noise and jamming fault of the pitch motor in a wind farm,through the disassembly and analysis of the fault motor,it was found that the failure point was the failure of the bearing at the brake end of the pitch motor.Based on the failure state of the bearing,combined with the motor structure and operating environment,the failure causes of the bearing were analyzed,and the design optimization suggestions for the pitch motor structure were proposed.