The main effects of spindle bearing oilair lubrication conditions, such as compress air flow rate, oil discharge interval, nozzle outlet diameter and oil viscosity were analyzed by a response surface method, which was used to design the experiment program. The analysis was carried out by using the TH6213 boring and milling machining center.The experiment results show that compress air flow rate and oil discharge interval have a great effect on the oil-air lubrication, and the interaction between them also has a great effect. While nozzle outlet diameter and oil viscosity have a small effect on the oilair lubrication, and the interaction between them has a negligible effect. The interaction between oil discharge interval and oil viscosity also has a negligible effect. When compress air flow rate, oil discharge interval, nozzle outlet diameter and oil viscosity are set to 80 L/min, 1.5 min, 2 mm and 2×10-5 m2/s, the temperature rise of bearing outring is lowest. The best oil supply quantity is 400 mm3/h. The conclusions have important significance to seek the best efficiency of oilair lubrication.