Abstract: The titanium alloy integral impeller is a complex tunnel type component. In the traditional milling process of rough machining the tunnels, the milling cutter is prone to deformation and vibration due to its long overhang, resulting in low cutting efficiency. Using plunge milling to process the tunnel in alloy integral impeller, the milling cutter feeds along the axial direction of the tool, resulting in less deformation and vibration of the milling cutter. A larger milling width and feed rate can be used, resulting in higher cutting efficiency. A simulation model was established for the machining the tunnel in titanium alloy integral impeller by plunge milling. The influence of milling speed, milling width, and feed rate per tooth on cutting force was studied through orthogonal experiments, and a regression empirical formula was established. The results show that the influence of milling width on milling force is most significant, and the influence of milling parameters on the three-dimensional cutting force of plunge milling is in the order of a_e>f_z>v_c. The efficiency of cutting can be improved by appropriately increasing the feed rate per tooth.