A drum washing machine comprising: an inner drum having a washing chamber for independently containing washing water, the inner drum being of a holeless structure and having a first operating state rotating in a clockwise direction and a second operating state rotating in a counterclockwise direction; an outer drum; an inner drum drainage port disposed in the inner drum; and a drainage sealing device installed at the inner drum drainage port to control opening and closing of the inner drum drainage port, the drainage sealing device comprising a drainage channel communicating with the inner drum drainage port and a blocking component that controls opening and closing of the drainage channel; characterized in that the drainage channel is disposed on an inner side wall of the inner drum, arranged in a circumferential direction of the inner drum and provided with a water inlet communicating with the inner drum and a water outlet communicating with the inner drum drainage port, the blocking component is of a one-way valve structure, the one-way valve structure comprising a valve ball configured to move between the water inlet and the water outlet of the drainage channel along with rotation of the inner drum, to thereby use the change of a rotation direction of the inner drum to switch the opening and closing states of the inner drum drainage port, wherein the valve ball keeps blocking the water inlet in the first operating state so that the drainage channel is closed and is far away from the water inlet in the second operating state so that the drainage channel is opened, or the valve ball keeps blocking the water inlet in the second operating state so that the drainage channel is closed and is far away from the water inlet in the first operating state so that the drainage channel is opened. an inner drum having a washing chamber for independently containing washing water, the inner drum being of a holeless structure and having a first operating state rotating in a clockwise direction and a second operating state rotating in a counterclockwise direction; an outer drum; an inner drum drainage port disposed in the inner drum; and a drainage sealing device installed at the inner drum drainage port to control opening and closing of the inner drum drainage port, the drainage sealing device comprising a drainage channel communicating with the inner drum drainage port and a blocking component that controls opening and closing of the drainage channel; characterized in that the drainage channel is disposed on an inner side wall of the inner drum, arranged in a circumferential direction of the inner drum and provided with a water inlet communicating with the inner drum and a water outlet communicating with the inner drum drainage port, the blocking component is of a one-way valve structure, the one-way valve structure comprising a valve ball configured to move between the water inlet and the water outlet of the drainage channel along with rotation of the inner drum, to thereby use the change of a rotation direction of the inner drum to switch the opening and closing states of the inner drum drainage port, wherein the valve ball keeps blocking the water inlet in the first operating state so that the drainage channel is closed and is far away from the water inlet in the second operating state so that the drainage channel is opened, or the valve ball keeps blocking the water inlet in the second operating state so that the drainage channel is closed and is far away from the water inlet in the first operating state so that the drainage channel is opened.