Optimization design of some small centrifugal compressor with a small stall margin was discussed in this paper.In the optimization design

a method called arbitrary camber lines blading design method was used for both axial and centrifugal compressors.The optimization design method

beginning with a through flow calculation

and in combination with arbitrary camber lines blading

applied three-dimensional computational fluid dynamics calculation to analyze the result of the optimization design.By changing the control properties of through flow design and arbitrary blading

meridional flow passage and three-dimensional blades were gained satisfactorily.As a result

not only the stall margin has been increased

but also the stage performance of the compressor has been improved significantly.