Abstract: Compared with fixed structure whose strength is only taken into account, for the movable ventilation window, the stiffness of its structure should be considered as well under the bird-striking because feathers can be squeezed into the gaps caused by part deformation under the bird impact load, making the gaps larger. In order to understand this process, a numerical model in which birds were modeled with SPH element and without feathers for the ventilation window under bird-striking was first established based on the PAM-CARSH software, and a revolute pair mechanism model by properly selecting the freedom of beam element. The numerical results and the real bird impact experiment results were compared, and the influence of feathers on the impact process was analyzed. The analysis results show that the feathers could significantly impact the gap size, thus, should be considered in the structure with gaps.