The trajectory control of aircraft when encountering low-altitude windshear in approaching is studied.A realistic engineering model of windshear and a nonlinear mathematical model of aircraft are established.Singular perturbation theory is applied to divide the dynamic system into several simple subsystems, and the Nonlinear Dynamic Inversion (NDI) method is employed for designing the control law for slow-state/fast-state subsystem and guidance system of outside loop.PID control method is also adopted for compensating the system inversion error arising from the perturbation of aircraft aerodynamic parameters caused by windshear and other exterior factors, which effectively eliminates steady state error of the system and keep effective control to the flight path of aircraft approaching.Finally, the simulation results indicate that the proposed NDI-PID controller has good dynamic characteristics and robustness, which can effectively resist the windshear interference with certain strength.