A method combining finite element analysis and oil monitoring was proposed to predict the fatigue wear life of wind turbine bearings.Based on finite element analysis by ABAQUS,the stress distribution and time stress history of wind turbine generator bearing can be obtained by combining with the actual operating conditions of a wind turbine.The fatigue wear life of bearing can be calculated by using rainflow cycle counting algorithm and Miner’s rule.Based on oil monitoring analysis and ferrography analysis,the grease properties and wear debris information of the bearing can be obtained,and the lubricating and wearing condition of the bearing can be judged.By combining the results of simulation and experiment,the fatigue life and failure of the bearing can be predicted and diagnosed more accurately,so as to improve the operation reliability of the wind turbine.