In order to design efficient flexures for the insect-like flapping-wing micro aerial vehicle, researches on heterogeneous compound flexures in electromagnetic flapping-wing aerial vehicles were conducted, taking into consideration the geometric constraint, stress and critical buckling conditions. The flexure design methods were given. Besides, the effect of the orientation of flexures on the overall parallel stiffness and that of the pre-stressing on the overall serial stiffness were also examined. Flexure dimensions of width, thickness, length and rotational stiffness for transmission gear were provided. The simulation results show that the overall serial stiffness is 135 times as big as the overall parallel stiffness, making possible highly efficient energy transmission. Moreover, the peak-to-peak stroke angle can reach 99.6°, which meets the design requirement for the insectlike flappingwing micro aerial vehicle.