The cylindrical milling method of divided area was proposed to improve the quality and efficiency of integrated impeller Based on the principle of inclined offset surface, the calculation and generation of NC cutter location for small divided area of blade were introduced In addition the computer simulation and the path chart of cutter center were given to prove the tool path The result shows that the change of cutter axis vector is distributed very well, and no interference occurs between the cutter and the impeller Further more the efficiency and the quality of machined surface were improved