This article takes the design of the steel containment vessel through sleeve for the third generation nuclear power plant AP1000 as the research background. Based on the large-scale general finite element software ANSYS, a three-dimensional solid finite element model was established, and on this basis, the bearing capacity of the through sleeve under high temperature, high pressure, earthquake, tornado and other loads was analyzed. According to the American ASME standard, the stress intensity of the containment vessel cylinder, reinforcement plate, and penetration component were evaluated separately, and the evaluation results showed that the design meets the requirements.