Abstract: A cross-sectional shape generating method for subsonic inlet design was proposed according to curvature regulation.This unique method can realize the transition of an arbitrary entrance shape to the exit circular shape easily and smoothly.Utilizing this method,an inlet design procedure was programmed,which could accomplish the surface composition of subsonic inlet with complex cross-sectional shape and complex bending style quickly and graphically.As a preliminary application,several diffusers with different entrance shape were generated and especially the design procedure of a slot-shaped inlet like that of X-47 vehicle was described in detail.