Abstract: During finite element analysis of large aircraft structures, the bolt connection is usually simplified to beam element, spring element and other linear connections, the influence of details such as bolt preload and assembly clearance cannot be considered. Therefore, a calculation and application method of nonlinear stiffness of bolted connection structure of windscreen frame was proposed. The stiffness model of the bolt of windshield window frame was established by this method.The deformation process was analyzed and the nonlinear stiffness curve of the bolt and the glass component during the extrusion process was obtained. The results show that compared with the linear connection stiffness model, it takes into account the influence of nonlinear detailed features on connection stiffness, the calculation result of bolt connection load is more accurate. The method is suitable for the optimization analysis of the connection structure between the windshield transparent part and the window frame, which can effectively avoid the redundant design and insufficient safety margin.