Abstract: In order to solve the problems of low production efficiency and high labour costs in a mobile phone housing inspection line, the bottleneck of inspection line is analyzed based on the data obtained from work measurement and Flexsim simulation technology. From two aspects of the operation mode and the workstation layout, the inspection line is optimized and re-designed by using method engineering. With the help of Flexsim, simulation test is carried out to evaluate the implementation effect of the optimization scheme. In the case of cost reduction, the workstation load and production efficiency are improved after the adoption of the new scheme. The results show that the combination of IE method and simulation technology can make the improvement of the manufacturing system more effective.