In aircraft structural design, integral joint is a common form of structural connection and an important force transfer structure, and its design is related to the flight performance and safety of aircraft. At present, the numerical calculation methods such as entity finite element method are commonly used in the design and analysis of integral joints in aircraft development. But in engineering practice, due to the self-locking of the partition unit, the calculation results are very different from the actual situation, and finally the joint can not meet the design requirements. In this paper, the self-adaptive grid method is adopted to solve this kind of problem effectively.