Abstract: In this paper, the principle of generating circle instead of interpolation circle is put forward, and a special spindle structure is designed to realize the process of milling instead of boring. The orthogonal method is used to design the cutting experiment, and the influence of different process parameters on the hole feature accuracy (size accuracy, roundness, hole wall roughness) is analyzed, and the feasibility of milling instead of boring is verified, and the main process parameters affecting the hole feature accuracy are studied. The results show that in the process of milling instead of boring, the biggest factor affecting the hole feature accuracy (size accuracy, roundness) is the axial feed speed, followed by the spindle speed; and the biggest factor affecting the hole feature accuracy (hole wall roughness) is the spindle speed. Finally, an automobile gearbox shell parts are selected for the actual test, and the milling instead of boring processing and boring processing are compared. Compared with the boring method, milling instead of boring can save the cutting tool cost and the processing time. The experimental results of this paper have important reference value for the research of advanced hole processing technology.