This paper is proposed a flapping wing aircraft based on the crank slider mechanism to solve the problems of the two flapping wing structures, such as synchronization and excessive local stress common to existing ornithopters. MATLAB is used to solve the equations to determine the dimensions of the individual components, and the 3D model is designed by SolidWorks software. The static analysis on flapping wings, the static stress, and the static strain distribution map of flapping wings are carried out. Moreover, the mechanism of flapping wing aircraft is modeled in Adams software, which simulates the actual structure by designing the kinematic constraint relationships between the components. It was concluded that the flapping wing could achieve a flapping angle of 30 degrees in one cycle, which was consistent with the simulation results by MATLAB. Furthermore, it was found that the first principal stress of the danger point was less than the yield strength of the material to determine the rationality of material selection. Finally, the fluid trace distribution on the upper and lower sides of the flapping wings was analyzed, which was consistent with the actual situation.