Composite air valve is one normal type of exhaust valve in the long big piping transport, which is normally mounted on the top of the pipe or pipe air holding place to discharge the air in the pipe, When the power supply for the pump is off, pump is stopped working, there will be negative pressure inside of pipeline, there will be vibration or break happened. Then, the air valve will work to suck into air quickly, keep the pressure inside the pipeline to be safe, making sure the pipe work normally. This air valve can remove the air existed in the pipe more flexible, preventing of the pressure fluctuation or other damages in the piping system. Double orifice air valve is applicable especially to the main water pipes and deep well pumps piping system.