Abstract:To research the influence of attack angle on the bionic robo-fish in dive motion,the robo-fish dive motion control rules was made, the lift with generation mechanism and influence factors was analyzed, and the swing model of pectoral fin was established.According to the geometry model of pectoral fin, the pectoral fin of robo-fish two-dimensional grid model was established by applying the software of Gambit.And applying Fluent software simulation, the robo-fish lift and resistance difference under different attack angle was analyzed, the pectoral fin optimal angle of attack is about 20° at flow velocity of 0.5 m/s in hydrodynamic environment with doing periodic swing was determined.