In order to study the flapping mechanism of flapping wing aircraft and the flow field around the wings, the flapping wing mechanism of pigeon shaped flapping wing aircraft was designed and the flow field around the wings was analyzed.The crank rocker mechanism parameters that met the requirements of flapping wing motion were calculated by using the graphical method of four-bar mechanism, and the relevant parameters were optimized. The flow field of flapping wing was simulated based on computational fluid dynamics (CFD); the velocity cloud, turbulent kinetic energy cloud, lift and thrust characteristic curves of the flow field around the flapping wing were obtained by using Fluent software. The results show that the pigeon shaped flapping wing flight will causes the change of flow velocity in the wing flow field, which leads to the change of air flow state from laminar flow to turbulence, and the turbulent kinetic energy provides the power for flapping wing flight.