Abstract: The function of fuel assembly top connection is to provide structure continuity and ensure the structure stability of fuel assemblies, so it plays an important role in the safety and performance of fuel assemblies. In order to analyze and evaluate a new-type fuel assembly top connection structure, considering contact nonlinear, material nonlinear and large deformation, a numerical simulation model is established in this paper by using ABAQUS. By comparison of the simulation result and the experimental result, the established finite element model is considered to be reasonable, and can be used to analyze and evaluate this new-type top connection structure. Finally, the tensile process of the top connection is analyzed in detail, and it is concluded that the friction force is the key factor for its tensile capacity.