In this paper, we regard insects wing as a flexible wing and use the flexible wedge-effect to explain the reason for the creation of high lift when insects flying. We disclose the fact that the flexible wedge-effect for insects flying and the fishtail effect for fish swimming have the same core—the force needed for creature movement comes from the flexibility and rhythmic locomotion. The most important bionic meaning of this kind of explanation is that it will be the developmental trend for the driving mode of the future bionics flapping aircraft that the wing is exerted some simple rhythmic locomotion in the state of the self-adaptability distortion. The easier the bionic motion simulation is, the more stable it can be realized. The bionics flapping aircraft research team of the Southeastern University has designed and made a prototype of the bionics flapping aircraft with flexible wing and successfully finished several outdoor test-flies.