The over-temperature fault of high-speed shaft in a wind power gearbox was studied.Based on the condition monitoring data before and after the gearbox fault is triggered,it was preliminarily determined that the cause of the fault was that the lubricating oil flow cannot meet the requirements.The lubricant flow required by the bearing was calculated and compared with the measured flow of the bearing,it was determined that the main reason for the bearing over-temperature alarm was that the actual lubricant flow of the high-speed bearing under low temperature environment was too little.A rectification scheme was put forward by adding a oil pipe to provide lubrication oil for the high temperature alarm bearing when keeping the crude oil circuit unchanged,and the flow of the increased oil circuit was calculated.After the rectification,the results of several times of full power operation show that the bearing temperature is normal,which verifies the feasibility of the rectification scheme.