Abstract: An aerodynamic design of a small centrifugal compressor for some pilotless aircraft was presented in this paper.One-dimensional thermal calculation was conducted to configure the flow path.And based on two-dimensional through flow design,the required aerodynamic performance was obtained by adjusting the distribution of velocity circulation of the blade rows.Then three-dimensional blade airfoils can be got by arbitrary camber lines blading.At last,three-dimensional CFD(computational fluid dynamics) calculation was used to analyze the result of the aerodynamic design.All performance parameters of the centrifugal compressor meet the design requirement at design point.And the performance curves at all speeds are really flat.Therefor the work stability of the compressor have a fairly broad scope.