The present invention discloses a flange structure at a bottom of an inner tub of a washing machine, comprises a shaft joint portion locating at a center of the flange and an annular mounting portion which is fixedly connected with the bottom of the inner tub of the washing machine and is at an outer periphery of the shaft joint portion, and a plurality of connecting portions being provided between the mounting portion and the shaft joint portion. The connecting portions include a main rib extending from the mounting portion to the shaft joint portion, and a plurality of transverse ribs are arranged on both sides of the main rib along an extending direction of a main rib respectively in turn, and a filter portion is formed by the plurality of connecting portions cooperating together, which is a region between the mounting portion and the shaft joint portion.
