In the process of engine operation,the wear condition of crankshaft journal at different corners is different,which results in the reduction of the matching accuracy of crankshaft surface.Based on the stress and strain analysis of the crankshaft of the internal combustion engine,a 3D model of the crankshaft of the in-line six-cylinder was established based on the finite element method.According to the actual load of the internal combustion engine,constraints and loads were applied to the crankshaft and static simulation analysis was carried out.The results show that the maximum stress on the crankshaft occurs at the transition corner between the crankshaft journal and the crank pin,and the maximum deformation occurs in the center of the crank pin.The optimal analysis of crankshaft based on response surface method shows that:after optimization,the maximum stress and maximum deformation of the crankshaft are reduced,among which the maximum stress is reduced by 12.42% and the maximum deformation is reduced by 16.83%.To verify the feasibility of the optimization,an enterprise survey was conducted on the optimized crankshaft.Combined with the crankshaft failure rate and repair situation of the enterprise,it is concluded that the structure of the crankshaft can be effectively optimized by the response surface optimization method to improve the strength and reliability of the crankshaft.