Aerial recovery, dense flight and aerial refueling of unmanned aerial vehicles (UAVs) all involve flight stability and position control of the vehicle in a close-range interference flow field. In view of the background of UAV lateral recovery and release, adopting interference aerodynamic derivative model, the research work has established the longitudinal small disturbance equation of motion of the vehicle in the close interference flow field, and has proposed using the rudder deflection to simulate the restoring force to achieve the longitudinal positional stability of the UAV. Using typical vehicle data, adopting the state space analysis method, establishing the cost function, the research work has completed the optimal control design of pitch rudder deflection and variable thrust , simulated and verified the method of achieving the UAV longitudinal close-range-flight stability control, and has preliminarily verified the feasibility of close-range-flight stability.