Rapid floating and sinking method and device for submarine

The invention discloses a rapid floating and sinking method and device for a submarine, and belongs to the technical field of ship manufacturing. The traditional method for discharging ballast water by using compressed air is changed into a method for discharging water and feeding water by partially discharging water by using compressed air and partially driving a telescopic closed small and medium-sized tank to stretch and retract by using a hydraulic jack; the small tank is an N-times expanded plate of a telescopic cylinder of the hydraulic jack without the central ejector rod; the jack is mounted in the small tank and is connected up and down, and the telescopic tank is mounted in the water ballast space; the telescopic tank can be used as a gas storage bottle and can also be used as a layer of protective armor; the jack drives the large-size empty tank to stretch out and draw back to drain water and feed water, the lever amplification effect can be achieved, the submarine can float and sink more quickly,