Abstract: As the main parts of the engine, the aircraft engine casing is usually made of superalloy blanks. This paper focuses on the optimization of milling force and other evaluation indexes to improve the machining efficiency and machining quality. Firstly, we studied the machining technology of the casing, and applied DEFORM-3D software to conduct milling simulation analysis on the rough milling process of the casing made of nickel-based alloy GH4169. The milling force was taken as the evaluation index, and the changing rules of the milling force under different milling parameters were obtained. Secondly, the influence of different indexes on milling force is analyzed, and the parameters are fitted according to the simulation results, and the prediction model of milling force is established. Finally, a set of optimal milling parameters are captured by using genetic algorithm, which provides guidance for the actual machining of the casing.