Tooth-locked quick-opening pressure vessel is widely used. The fast opening structure was an important part of the pressure vessel door opening and closing operation and the meshing degree of the tooth determined the safe of the container's operation. A tooth-meshing autoclave was taken as an example and the finite element analysis was used as a method to carry on the numerical simulation to its meshing tooth in load condition and the strength check to its dangerous path. In the case of the incomplete meshing in the circumferential direction, the incomplete meshing in the radial direction and the combined operation in which the two directions were not fully meshed. According to the analysis results, it could be seen that with the decrease of meshing tooth circumferential or radial meshing degree, the stress increased. Under the dangerous working condition of combined meshing (i.e.circumferential meshing degree was 80%, radial dislocation was 3.0 mm)，the tooth's stress reached the maximum. After the strength check, the primary local membrane stress exceeded the allowable value, so the stress didn't meet the requirements. According to the analysis results, the quick-opening container should be avoided to working with incomplete meshing tooth to ensure the safe use.