A laundry treatment device, comprising: an inner tub, configured to hold water, and be provided with a drainage hole; a driving device; and a drainage valve assembly, comprising: a valve core, having a sealing position for sealing the drainage hole and a drainage position for opening the drainage hole; a transmission rod mechanism, connected to the inner tub, and having a rotation center line, a first end of the transmission rod mechanism driving the valve core to move, and during rotation of the inner tub, the driving device operative to selectively toggle a second end of the transmission rod mechanism to drive the transmission rod mechanism to rotate around the rotation center line; characterised in that an elastic positioning member and an elastic reset member, the elastic positioning member operative to keep the valve core at the sealing position or the drainage position, the elastic reset member operative to drive at least the second end of the transmission rod mechanism to be reset; wherein the transmission rod mechanism comprises a transmission rod, a first shifting rod, and a reversal mechanism connected between the valve core and a first end of the transmission rod, the transmission rod mechanism drives the valve core to translate through the reversal mechanism, the first shifting rod is connected to a second end of the transmission rod, and the driving device selectively toggles the first shifting rod; wherein the valve core has an intermediate critical position between the sealing position and the drainage position, such that when the transmission rod mechanism drives the valve core to cross the intermediate critical position, the elastic positioning member is operative to drive the valve core to continue to move to the sealing position or the drainage position, and the elastic reset member is operative to drive at least the second end of the transmission rod mechanism to idle to be reset; wherein the elastic positioning member is a second torsion spring comprising a spiral body, a first rotation arm and a second rotation arm, the first rotation arm is fixed relative to the inner tub, the spiral body is suspended, and the second rotation arm is operative to move along with the valve core or the transmission rod mechanism; wherein the second rotation arm is connected to the valve core, and when the valve core is positioned at the sealing position, an acting force applied by the second torsion spring to the valve core has at least a force component parallel to a movement direction of the valve core and facing toward the drainage hole, and when the valve core is positioned at the drainage position, an acting force applied by the second torsion spring to the valve core has at least a force component parallel to the movement direction of the valve core and away from the drainage hole, and when the valve core is positioned at the intermediate critical position, an acting force applied by the second torsion spring to the valve core has a direction perpendicular to the movement direction of the valve core. characterised in that an elastic positioning member and an elastic reset member, the elastic positioning member operative to keep the valve core at the sealing position or the drainage position, the elastic reset member operative to drive at least the second end of the transmission rod mechanism to be reset; wherein the transmission rod mechanism comprises a transmission rod, a first shifting rod, and a reversal mechanism connected between the valve core and a first end of the transmission rod, the transmission rod mechanism drives the valve core to translate through the reversal mechanism, the first shifting rod is connected to a second end of the transmission rod, and the driving device selectively toggles the first shifting rod; wherein the valve core has an intermediate critical position between the sealing position and the drainage position, such that when the transmission rod mechanism drives the valve core to cross the intermediate critical position, the elastic positioning member is operative to drive the valve core to continue to move to the sealing position or the drainage position, and the elastic reset member is operative to drive at least the second end of the transmission rod mechanism to idle to be reset; wherein the elastic positioning member is a second torsion spring comprising a spiral body, a first rotation arm and a second rotation arm, the first rotation arm is fixed relative to the inner tub, the spiral body is suspended, and the second rotation arm is operative to move along with the valve core or the transmission rod mechanism; wherein the second rotation arm is connected to the valve core, and when the valve core is positioned at the sealing position, an acting force applied by the second torsion spring to the valve core has at least a force component parallel to a movement direction of the valve core and facing toward the drainage hole, and when the valve core is positioned at the drainage position, an acting force applied by the second torsion spring to the valve core has at least a force component parallel to the movement direction of the valve core and away from the drainage hole, and when the valve core is positioned at the intermediate critical position, an acting force applied by the second torsion spring to the valve core has a direction perpendicular to the movement direction of the valve core.