Abstract: In this article, two machining processes are designed for the parts with axial arc groove on the inner hole surface; then the machinability of the two processes, the difficulty of machining axial arc groove and their relative advantages and disadvantages are analyzed. The analysis results show that process route 2 is the optimal processing method. In order to ensure the machining quality of the product, when the part is machining in accordance with process route 2, the tools and the processing parameters should be reasonably selected, and the spindle speed, feeding speed and feed are set to 1 000 r/min, 50 m/min and 0.5 mm/r respectively during rough machining; and the spindle speed, feeding speed and feed are set to 1 200 r/min, 25 m/min and 0.1 mm/r respectively during finishing cut. When the milling machine is used for hole drilling, the drilling amount is set to 0.07 mm/r, and the spindle speed is 800 r/min. By comparing and analyzing the two different processing technologies, the optimal processing method is determined, which provides reference for processing the similar structures.