Abstract: The high pressure vessel is the key component of pressure refining. Based on the optimality criteria method and finite element results, an optimization design method is illustrated through a classical pressure vessel design. Firstly, the technical specification and design parameters are given, and the mathematical model of the optimization design is constructed by taking the weight minimization as the optimization design objective; secondly, the 3-D finite element model of the vessel is built by the preprocessing software Hypermesh and the commercial finite element software Abaqus, and the objective function is obtained through finite element analysis; thirdly, based on the fully stressed method and the characteristics of the vessel structure and the load, the iterative formula of the optimization algorithm is given and is applied to the optimization design of the high pressure vessel; at last, the safety assessment, the modal analysis and the stability analysis of the designed high pressure vessel are performed. The results show that the designed pressure vessel meets safety requirements, the dynamic characteristic meets design requirements. Moreover, stable analysis shows that global unstability is prevented for the designed pressure vessel under unexpected exernal load conditions.