The oil-air separation Filter Element is a key component that determines the quality of compressed air discharged from an oil-injected screw compressor. The air compressed from the head of the screw compressor entrains oil droplets of different sizes. Large oil droplets are easily separated through the oil and gas separation tank, while small oil droplets (suspended) must pass through the micron glass fiber of the oil and gas separation filter element. The filter material is filtered. The correct choice of glass fiber diameter and thickness is an important factor to ensure the filtering effect. After the oil mist is intercepted, diffused and polymerized by the filter material, the small oil droplets quickly aggregate into large oil droplets, pass through the filter layer under the action of pneumatic and gravity, and settle at the bottom of the filter element. The oil passes through the inlet of the oil return pipe in the recess at the bottom of the filter element and continuously returns to the lubrication system, so that the compressor discharges relatively pure compressed air.