Abstract: Part machining can be imagined as a modeling procedure within which only a series of Boolean subtracting between father body and child body happen. To obtain such a series of subtracting body, Destructive Solid Geometry(DSG) theory is applied to orderly decompose the part design model into corresponding manufacturing model. Facing the prevalent featured-part of rotational model and that of prismatic model, two key algorithms based on the feature tree description that records the procedure of feature modeling are presented: width-first searching & depth-first searching,respectively implementing manufacturing planning of feature machining in the space span & time span. Finally, an expatiatory example goes further into the relative concepts and algorithm thread.