This paper presents a method fur impeller modeling and 5-axis machining by the reverse engineering. The impeller is composed of pressure surface, suction surface and leading edge, and so on. The surfaces can be modeled by using the characteristic curves such as hub curves, shroud curves and fillet curves. The characteristic curves are extracted from the scanned data and the inspection is performed between the surfaces generated by using the characteristic curves and the scanned data. Then, An impeller is machined by 5-axis mainlining and post-processing with inverse kinematic solution.