Abstract: Vacuum vessels are widely used in the aerospace field, and their structural stability is an important indicator for assessing the design. To address the uncertainty of the rule design of complex shaped vacuum vessels and the accuracy deficiencies of simulation assessment, this paper constructs a large vacuum vessel model and analyses the vessel stress, displacement and buckling indicators under the conditions of process equipment mass, 0.1 MPa external pressure and gravity. A vacuum vessel structural stability test system consisting of strain, displacement and pressure tests was set up, and two evacuation modes, sectional and continuous, were used to obtain the stress and displacement test data of the classical measurement points, and a test evaluation method for the structural stability of large vacuum vessels was proposed. The results show that the method can effectively verify the accuracy of the design calculation and finite element simulation of the vacuum vessel. The method provides an optimization direction to improve the accuracy of the simulation, which is helpful for the development and acceptance of the vacuum vessel.