Provided is a highly-efficient oxygen-increasing method. The highly-efficient oxygen-increasing method comprises an oxygen-increasing tank. The oxygen-increasing tank comprises a tank body, in which an oxygen supply device and a residual oxygen recovery device are arranged. A deflection baffles are arranged on the inner wall of the tank body. The tank body is provided with a water supply port, an oxygen supply port and a water outlet. The oxygen supply device comprises an oxygen supply pipeline and oxygen supply aeration boards. The oxygen supply port is connected to the oxygen supply aeration boards through an oxygen supply pipeline. The oxygen supply aeration boards are provided with first micropore channels. The residual oxygen recovery device comprises a residual oxygen recovery pipeline and residual oxygen aeration boards. A recovery end of the residual oxygen recovery pipeline is placed at the top of the tank body. A releasing end of the residual oxygen recovery pipeline extends downwardly to be connected to the residual oxygen aeration boards. A second micropore channel is arranged on the residual oxygen aeration boards. The highly-efficient oxygen-increasing method has the following beneficial effects: the enclosed tank body is used for circulated oxygen increase in order to increase oxygen dissolving rate; the deflection baffles are arranged in a staggered mode; the oxygen-dissolving paths of water flows in a oxygen-dissolving layer can be maximized; microporous aeration is utilized for breaking gas into tiny grain sizes; oxygen dissolving rate is increased; the oxygen-increasing efficiency is high; oxygen waste is little; and the highly-efficient oxygen-increasing method can be used for high-density transport and culture of living fish.