The horizontal tail is eliminated from the flying wing layout for improved the low observable and aerodynamic efficiency, resulting in poor longitudinal maneuverability and fight stability. The low speed wind tunnel test study on the improvement of longitudinal aerodynamic characteristics of large aspect ratio flying wing model was carried out by using plasma flow control technology. The flying wing model has a 34.5 degree leading-edge sweep angle and 5.79 aspect ratio. The reasons for the deterioration of the static maneuverability and stability of the flying wing model and the mechanism of plasma control on the flow field and longitudinal aerodynamic characteristics were studied by particle image velocimetry (PIV) flow visualization and static force measurement test. The control law of plasma control on the flight maneuverability and stability of the flying wing model was studied by virtual flight test. That the flow separation of the outer wing of the flying wing model occurs earlier than the inner wing and the wing is swept back result in the forward movement of the aerodynamic center and the deterioration of the longitudinal static stability. The shock disturbance induced by plasma can suppress the flow separation of the suction surface, thereby extending the linear section of the lift curve of the model, preventing the aerodynamic center from moving forward, and improving the longitudinal static stability. When the wind speed is 50m/s, the plasma control improves the horizontal rudder efficiency at the high angle of attack of the flying wing model, increases the maximum lift coefficient of the model by about 0.1 and postponed the stall angle of attack by more than 4 degrees at different rudder angles. Plasma control allows the flying model to follow the command movement better while flying, increases the flying pitch limit angle from 11.5 to 15.1, reduces the amplitude of longitudinal disturbance motion by 2 degrees, and reduce the oscillation attenuation time from 15 seconds to 8seconds, thereby improving the longitudinal flight maneuverability and stability of the flying wing model. It can be seen that plasma flow control technology has great application potential in improving the flight quality of flying wing layout.