The internally blown flap is of efficient lift enhancement ability, but stall angle of attack drops significantly at a higher jet momentum. In order to improve the stall characteristics, this paper studies the stall characteristics of the internally blown flap with the droop nose. The flow fields of a subsonic airfoil with droop noses combined with seamless flaps under the effect of circulation control are obtained based on numerical simulation. The influence of the blowing momentum coefficient on the stall characteristics is studied. The effects of leading edge rigid deflection, camber and thickness changes on the improvement of stall characteristics are studied. The effects of doop nose with different flap angle are also studied. It reveals that as the blowing momentum coefficient increases, the stall angle of attack first drops rapidly and then slightly increases. The leading edge droop devices reduce the pressure gradient on the upper surface of the airfoil, delay the trend of the momentum thickness of the foil boundary layer increasing with the angle of attack and delay the stall angle of attack effectively. By gradually changing the curvature of the leading edge surface, the leading edge droop design has the best effect on the improvement of stall characteristics.