Abstract: The principle error in the tool path planning and the deformation error in the machining process are the most important error sources in the flank milling of thin-walled blades. The modeling and analysis of deformation error is introduced into the flank milling of tool path optimization model, a new method of flank milling deformation error compensation and tool path planning is proposed. This method is applicable to the flank milling of thin-walled blades on both straight and quasi-straight surfaces, and can generate tool paths with the least comprehensive error. The simulation results show that the error calculated by this method is more accurate and effective than the traditional tool path plan-deformation compensation strategy, which improves the efficiency and reliability of tool path planning for flank milling.