Based on the characteristic of the bird impact accident, the 3-D model of the wainscot structure is modified. A finite element calculation model has been built in the PAM -CRASH environment. The numerical result accords well with the experiment. Several optimization plans have been assumed according to the analysis result. A numerical simulation has been conducted to the optimization plans which are compared in assembly and structure weight range. The simulation results indicate that the anti-bird impact ability will be enhanced by strengthening the stiffness of the weakness point of the wainscot structure.