In order to deeply investigate the lift mechanism of hovering flapping flight and its characteristics, the high lift mechanism during moth flapping is investigated by numerical simulation and experimental design, and the hovering flapping wing model in water is designed. Numerical analysis shows that there are significant leading-edge vortex (LEV) attachment and rotating circulation mechanisms during flapping up and down. Based on scaling laws, the designed in-water flapping wing model agrees with the real moth in terms of Reynolds number and Strouhal number, which verifies the geometric similarity of the flapping wing. Based on the moth flight parameters, the flapping wing flapping kinematic equations are established and solved using MATLAB to design the relationship between the crank rotation angle and the flapping amplitude and the stroke ratio, and the crank-slip mechanism is used to realize the same frequency flapping to meet the kinematic requirements and motion similarity. The numerical analysis study and experimental design provide the theoretical basis and experimental support for further investigation of the mechanism of flapping wing motion and nonstationary characteristics.