To design the control logic during the penetration of windshear, Non-linear Inverse Dynamics (NID for short) method has been employed to achieve the decoupling of the non-linear flight control system and the implementation of the real-time/on-line control for the flight trajetory. Two independent control laws were developed: climb rate/airspeed control mode in the wind-coordinate systemand climb rate/ground speed control mode in the ground-coordinate system. On the basis of analysis of the two modes, they were integrated to form a new and more feasible penetration-trajectory control law: ground speed/airspeed control law. The simulative calculation results indicated that the NID method works effectively in the trajectory control of airplane during the penetration of windshear.