Aiming at the lightweight problem of the metal packing case body,the reliability analysis of the packing case body after response surface optimization was carried out,and a new method combining the response surface optimization theory and reliability analysis was proposed.The response surface was fitted by the central composite design method and the design variables were determined through parameter sensitivity analysis.The response surface was optimized under the condition of meeting the strength and rigidity of the box body,and the minimum mass of the packaged box body was obtained.Then on this basis,a three-dimensional model of the box was reestablished,and the reliability and Six Sigma level of the optimized box structure were obtained according to the strength and rigidity reliability evaluation criteria of the packaged box.The results show that the weight of the optimized box is reduced by 9.11%,and the reliability of the box is 97.50%.This not only improves the strength and static rigidity of the box,but also reduces the weight of the box and ensures the reliability of the box.It provides new ideas for the design of other large construction machinery.