The oil injected rotary screw air compressor is a type of positive displacement compressor with superior and reliable performance, low vibration, low noise, high efficiency, few wearing parts, easy operation and maintenance. It adopts a high-efficiency motor to drive the rotary screw airend rotating for air compression. The precise matching between the male and female rotors and between the rotors and the airend housing reduces internal air leakage and improves efficiency. Only the rotors mesh with each other, without the reciprocating motion of piston cylinder, which reduces the vibration and noise level. Relying on the pressure difference generated by itself, it continuously injects lubricating oil into the compression chamber and bearings, simplifying the complex mechanical structure. The injected lubricating oil forms an oil film between the rotors, increasing the air tightness of the compression, improving efficiency and reducing high-frequency noise. The compressed air/oil mixture discharged from the airend enters the aftercooler for cooling after separation, reducing the temperature and improving the quality of the compressed air.