Impellers are important components in the field of precision machine, energy technology, and aerospace industries. Due to their complex geometries and higher degrees of interference, to produce a impeller with high precision dimension is a challenging technology. In this study, flank milling is used to machine blade surfaces of impeller instead of point cutting. Flank milling can provide a surface better than point cutting without addition processes. When blades of an impeller are designed by ruled surfaces, the impeller can be machined by flank cutting technology. Based on the type of a five-axis CNC machine, the objective of this project is aimed to develop the technology of five-axis machining for impellers. The involved techniques are : the identification of undercutting in flank cutting for ruled surfaces, five-axis tool paths generation, coordinate transformations for five-axis machining, and determination of cutting parameters. In addition, a practical application example is provided to show the feasibility and effectiveness of the developed procedure.