The research is aimed to analyze the influence of aerodynamic performance of civil aircraft on airworthiness. It shows besides the suppression on noise source, airworthiness noise level can also be reduced by optimizing and improving the aerodynamic performance. For takeoff process of civil aircraft, with the lift-to-drag ration increasing, the flightpath angle will increase and the distance between aircraft and the flyover test point will increase too. This change has a little influence of lateral noise but it will reduce flyover noise. In the research, for every 1% increase of L/D(lift to drag ratio), the flyover noise will be reduced by 0.06 EPNdB. For the landing process of civil aircraf, with the maximum lift coefficient increasing, the reference approach airspeed will decrease, and the approach noise level will be reduced. When the maximum lift coefficient increases by 1%, the approach reference speed decreases by 0.5% and the approach noise level decreases by 0.10 EPNdB.