A new type valve was designed based on hydraulic principles and faucet. It would be turned off automatically when there was no water.The surface area of valve sleeve was different and the force was generated for the water pressure, then the valve would automatically be closed. A cavity would be formed between the sleeve and spool valve, because of the sleeve moved to the inlet side due to weight when the watersaving valve was open and anhydrous. The water pressure would go to the cavity through a small hole after the water inflow. Because the surface area of cavity bottom was greater than that of the outer bottom of the valve sleeve, so the valve sleeve would compress gaskets under pressure, at last it would turned off automatically when there was no water. The tests show that the new type valve can save water and have great promotion and practical value.