A control method for automatically positioning an inner tub. When the inner tub rotates to a certain position, a positioning pin at the bottom of an outer tub is released to press against the bottom of the inner tub, the inner tub continues to rotate, and when a positioning hole at the bottom of the inner tub is aligned with the positioning pin, the positioning pin stretches into the positioning hole, and thus the inner tub is locked. After the positioning pin is released, the inner tub continues to rotate under the effect of inertia, or the inner tub continues to rotate under the drive of a motor, when the inner tub rotates to the position where the positioning hole is aligned with the positioning pin, the positioning pin stretches into the positioning hole to achieve automatic positioning and locking of the inner tub.