A drainage structure of a washing machine has a central hole at the inner tub bottom of the washing machine, and an annular groove is arranged around the central hole; the inner part and the outer part of the inner tub communicate with a water flow passage on the annular groove, and the annular groove has a sealing member capable of reciprocating motion for controlling the on-off state of the water flow passage. The upper part of the sealing member has an elastic member for controlling the downward movement of the sealing member to contact the inner tub bottom and/or the bottom surface of the annular groove, and the lower part of the sealing member has a driving member for controlling the upward movement of the sealing member to separate from the inner tub bottom and/or the bottom surface of the annular groove.
