Abstract: To optimize the processing route in CAPP system,automatic generation of manufacturing setup planning in CAPP is studied.Based on the surface feature,mathematic model and algorithm to automatically generate setup planning has been formulated by means of feature and tolerance graphics(FTG).The algorithm can be used to solve such problems as setup sequences,datum selection,the number of setup,and then setup planning.The setup route achieved in this way can minimize the influence of locating error stack-up on the machining quality.Finally a case study of setup planning is presented to verify the feasibility of the method.