The boundary layer control method by blowing is applied to the tail of amphibious plane to improve the steering ability of rudder. Using the CFD numerical simulation method, a two-dimensional scheme for the boundary layer control of the tail of a large amphibious aircraft was studied, design a seam baffle between the vertical stabilizer and the rudder, so as to prevent the high-pressure air flow on the windward side from hitting the leeward surface, Obstructing the air-blowing adhesion; The combined blowing scheme of the front edge of the tail stabilizer surface was studied to prevent the rudder from stall earlier. The results show that the steering ability of rudder is increased by about one times after the vertical tail is controlled by a blowing and combined with a seam baffle and a combination of blowing.