When the civil aircraft fall into the area of stall angle of attacks,air force will show hysteresis,steep drop and other strong nonlinear characteristics,and the track becomes unstable. To solve the problem,bifurcation analysis method is applied to analyze the control characteristics of aircraft near stall region, and its oscillation region, multi-equilibrium points are obtained.Based on the nonlinear optimal control theory,aircraft stall recovery at high angle of attack is designed. With the Galerkin algorithm, the suboptimal controller parameters are claculated,and the simulation of the aircraft falling into stall and recovery when descending is verified.The results show that the controller can be well controlled to recovery from the stall and resume normal track.