In the digital assembly of the wing-fuselage， due to factors such as manufacturing errors and positioning errors， the assembly parts inevitably have a certain deviation before docking. During the docking process， the connecting structure may experience bumps， wear， and deformation. In order to avoid the above-mentioned situation in the wing-fuselage assembly， This paper designs a five-degree-of-freedom compliant docking mechanism. So the components can be flexibly adapted to interference during the docking process. The assembly can be completed smoothly according to the guidance of the target component. On this basis， this paper takes the fork-lug connection structure as the research object， and establishes the contact force prediction model by analyzing the contact force of the connection structure during the wing-body compliant docking process.