Abstract: An in-service wind tunnel vacuum spherical tank needs to add a DN1000 hole. The differences in strength, stiffness, and life of the spherical tank before and after adding holes were studied, and the reinforcing effects of various reinforcing schemes were compared. The following conclusions are obtained: additional holes will reduce the overall stiffness and service life of the spherical tank, but the impact is limited. Increasing the wall thickness of the hole outlet pipe has an obvious reinforcement effect on the overall stiffness and only reduces the stress peak at the opening point. The reinforcing ring can effectively reduce the stress peak of other parts of the original hole, and significantly improve the service life of the spherical tank after the newly opened hole. However, the relationship between the local stress of the newly opened part, the stiffness of the spherical tank and the width of the reinforcing ring is non-monotonic; the width of the reinforcing ring should not be too wide. The research results prove that the performance of the vacuum spherical tank still meets the design requirements after adding DN1000 hole, and provide theoretical support for the formulation of the super-large volume vacuum spherical tank reinforcement scheme.