A closed circulation system for improving an operating efficiency of a gas drainage pump, comprising a pneumatic diaphragm pump, a drag-reducing polymer solution tank, the gas drainage pump, a submersible pump, and a compressed air pipe, wherein a liquid inlet of the pneumatic diaphragm pump is connected to a liquid outlet of the drag-reducing polymer solution tank, and a liquid outlet pipe of the pneumatic diaphragm pump leads to a circulation water pool;
- a pneumatic stirrer is provided inside the drag-reducing polymer solution tank a charging hopper is provided at a top of the drag-reducing polymer solution tank;
- a liquid outlet of the submersible pump is connected to a liquid inlet of the drag-reducing polymer solution tank and a liquid inlet of the gas drainage pump respectively through a first three way pipe, and a liquid discharge pipe of the gas drainage pump is connected to the circulation water pool;
- and the compressed air pipe is connected to the pneumatic diaphragm pump and the pneumatic stirrer respectively through a second three way pipe.