A new oil-air mixer for oil-air lubrication system was designed,and its working principle,structure design,flow pattern of the oil-air mixer and oil supply at the end of the oil and air pipe were studied.The fluid domain model including the spiral tube was established,and the whole fluid domain was divided into initial region of lubricating oil,oil-air mixing region,spiral tube region and end straight tube region.A transient model was established by using Fluent software to analyze the formation mechanism of oil-air two-phase flow in the case of a single oil injection,and a new theoretical model of oil-air mixing was proposed.The results show that the integral type oil-air mixer has a compact structure and can realize accurate and quantitative oil and air supply.The high-speed compressed air can divide the lubricating oil into two parts.One part of the lubricating oil is attached to the pipe wall and flows forward at a lower speed,and the other part flows forward at the center of the pipe with the air at a higher speed,so that the lubricating oil can be evenly distributed on the pipe wall of the whole pipe in a short time.