As the scale of superconducting accelerator construction grows, superfluidhelium systems providing the cryogenic environment for them are increasingly widely used. Most of the large-scale superfluid-helium system in international accelerator laboratories use the cold compressor as a pressure generating device. The impeller is the critical component of the cold compressor. CFturbo is adopted here to design the impeller. CFD (Computational Fluid Dynamics) is used to obtain the performance characteristics of the designed impeller.