Abstract: Two centrifugal compressor impellers with different meridional shape and blade angle were designed using computer-aided integrated design systems. The flow fields of the impellers were calculated by solving three-dimensional Navier-Stokes equations. Calculation results illustrate that decreasing the blade hub-to-shroud loading level can increase the impeller adiabatic efficiency, and that aft-loaded impeller can obtain higher impeller adiabatic efficiency. Changing meridional shape and blade angle can have large effects on the blade loading distribution.