According to the guideline requirement for certain penetrating aero guided bomb, a guidance control law based on multi-section composite guidance is designed, the mathematical model of control system composed of pitch, yaw and roll channel is built. In order to pitching loop as the analysis object, in the glide phase, the normal overload is taken as the controlled parameter, so as to keep the aero guided bomb flighting at maximum lift-drag ratio; In the transitional phase, the method of pitch angle control and early virtual proportional navigation is adoptted, aiming at ensuring the impact angle maximum and that the bomb can fall into preconcerted proportional navigation region, under the condition that the normal overload is less than the required overload; In the dive phase, virtual proportional navigation is taken to guide the bomb to the target and meet the requirement of attack angle and the CEP precision simultaneously. The optimal algorithm which optimize the control parameters of two key points is adopted to fulfill the demand of adaptive flight control for the aero guided bomb. Simulation results show that the control law of multi-section composite guidance can meet the requirements of the large impact angle, small attack angle, minimum impact velocity and the CEP precision, and also provide technical support for the engineering realization of the penetrating aero guided bomb.