In the process of minimal quantity lubrication (MQL) milling, the machining craftwork parameters have a significant influence on the cooling and lubrication effect of tool-chip and tool-workpiece contact interface. In this paper, the influence of the air flow field disturbed by the high-speed rotation of the milling cutter on the MQL jet angle and the penetration mechanism of the cutting fluid under the influence of the cutting zone pressure are analyzed by finite element simulation. Then, the titanium alloy TC4 commonly used in aerospace is used as the workpiece material, and the oil-onwater (OoW) as lubricating medium. The influence of the three parameters of the injection angle, injection distance and lubricating oil flow rate of the minimal quantity lubrication system on the milling force of titanium alloy is investigated by orthogonal experiment. And the optimal process parameters of the oil-on-water minimal quantity lubrication (OoWMQL) system are as follows: the nozzle angle is 30°, the injection distance is 10 mm, and the lubricating oil flow rate is 135 mL/h. Then, the effects of cutting speed and feed per tooth on the cutting performance of titanium alloy in dry milling and waterbased minimum quantity lubrication (WMQL) milling were studied by using the optimal process parameters of OoWMQL milling force, while OoWMQL technology significantly reduces the milling force under all parameters, and the maximum reduction range is about 50%. In addition, the OoWMQL method can significantly reduce the surface roughness, inhibit the generation of surface defects such as tool marks and adhesive chips, and effectively improve the machinability of titanium alloy.