A new method to generate 3-D body-fitted coordinate system for the channels of centrifugal impellers was described. The coordinate system is generated by solving a number of 2-D elliptical partial differential equations. Comparing with the method directly solving three 3-D elliptical partial differential equations for body-fitted coordinate systems, this method can save much computer time and storage. An example of coordinate generation for a centrifugal compressor impeller was given.