Although the five-axis machine tool presents excellent advantages of high-speed, -efficiency, and -precision machining of complex curved surface parts (impeller and blade), its actual motion demonstrates nonlinear principle error due to the participation of the rotating axis. Traditional methods, such as linear interpolation, Rotation Tool Centre Point(RTCP), and tool point optimization, can effectively control nonlinear errors despite their limitations. A regional compensation optimization method is proposed in this study to solve nonlinear error problems effectively in five-axis machining of complex curved surface parts. First, feature points of the complex free-form surface are identified, and regions are divided to distinguish the compensation optimization algorithm of each interval. Second, JAVA language is applied to develop a special postprocessor with nonlinear error partition compensation module. Finally, the BV100 machine tool is used as the experimental platform, and a turbine blade is utilized as the specimen for simulation and cutting experiments. Results showed that the surface quality and contour accuracy of machined parts improved when the nonlinear error regional compensation optimization algorithm is used.