For taking advantage of high speed machining(HSM) in complex curved surfaces as impeller, the virtual manufacturing technology is adopted before the real machining, which can eliminate tool collision interference phenomenon of the trial cutting, avoid complicated process of trial test , forecast machining results efficiently. The simulation tests were proceeded to the each impeller procedure NC program by using the VERICUT virtual manufacturing soft to modeling five-axis machine tool HSM600U, and the result compared with the real machining is identical with one other. So it is tested that applying this technology can forecast the machining process truly.