In the design of tail suspended nacelle aircraft, the aerodynamic effects of engine intake and exhaust on other components need to be paid attention to. In order to comprehensively study the influence of engine intake and jet flow on the aerodynamic characteristics of the whole aircraft, the numerical simulation of the flow field was carried out under the condition of a tail suspended nacelle aircraft cruise(H=11 000 m, Ma=0.78), focusing on the comparative analysis of lift and drag characteristics and flow field distribution between the nacelle ventilation model and with intake and exhaust model. The calculation results show that, the influence of engine intake and exhaust on the aerodynamic characteristics of the aircraft with close tail suspended nacelle is mainly reflected in the aerodynamic interference between nacelle and wing. In the studied angle of attack range (-2°~8°), the suction effect caused by the engine intake changes the pressure distribution on the surface of the wing and nacelle,increaseing the aera of the negative pressure zone on the upper surface of the wing. The strength of the shock intensity of the upper lip of the nacelle decreases, which makes the lift coefficient increase, the drag coefficient decrease and the lift-drag ratio increase. However, the improvement trend of the aerodynamic characteristics gradually slows down with the increase of the angle of attack.