Abstract: According to the uncertainty,the nonlinearity and the complexity features of UPP(unmanned powered parafoil), a 6-DOF nonlinear dynamic model for UPP is established.The response performance of UPP model to input signals is simulated and analyzed.A UPP online subspace prediction method is proposed which can overcome the effects of the uncertainty,the time-varying and the disturbance on the flight control system in time,and can keep constrained predictive control optimum in predictive horizon.Simulation results show that the method can identify the input and the output data generated by simulation model effectively,and it has excellent tracking performance and control precision.