Aiming at the complex surface of impeller, a rotary file is selected to process it on the basis of the platform of robotic automatic machining system. The coordinate transformation of F-type rotary file is theoretically deduced to facilitate the calibration of robot tool coordinate system. The finite element analysis of impeller material is carried out by ANSYS Workbench software, and the rules of workpiece deformation, stress and strain, tool deformation are obtained.