The workload calculation of inspection and repair process is the most difficult due to the randomness of defects in the automobile painting workshop.The lack of workload data restricts personnel optimization and efficiency improvement.This paper proposes a new method to calculate the workload of inspection and repair process.The author introduced the method of decomposition the process into smaller standardized models.The work time of the standardized models are calculated under the assistance of MTM and input of defect information.Afterwards,workload of every position are available and used to guide the personnel optimization and efficiency improvement.