Aiming at the technical problems that the numerical control (NC) programming quality of the casing parts for aero-engine is difficult to control effectively, and the efficiency and flexibility of NC programming are poor, this paper proposes an automatic programming solution for the typical casing parts for aero-engine. In order to improve the efficiency and quality of NC programming of the casing parts, the automatic programmed of NC machining programming is realized by customizing the automatic programming tool under the environment of UG CAM.