A kind of similar ruled surface integral impeller flank milling machining method was proposed based on inspection at original position. Firstly，the similar ruled surface was reconstructed for approximate ruled surface；then the similar ruled surface integral impeller flank milling judge conditions were proposed. For tool axial vector solved question of nondevelopment ruled surface，analytical method was proposed. Finally similar ruled surface tool path simulation and actual numerical control (NC) machining experiments were carried out, which verify the correctness of the algorithm.