An inverse problem method based on s 2 flow surface theory of 3 D flow field has been developed to design centrifugal compressor impellers for heavy gases and some techniques to improve the performance of high pressure ratio impellers have been presented too.Two impellers with Mach number M u 2 =1 26

1.06 and relative width b 2/D 2=0 054

0 036 respectively have been designed by use of this method.Experiments of the impellers have been performed in a closed loop test rig with Freon gases (R11) to verify the design method.The dynamic pressures distribution from shroud to hub at the exits of impellers and the losses of vaneless diffusers and volutes have been measured and analyzed under different work points.Their good performance obtained from tests shows the design method and techniques presented in this paper is feasible and favourable.