The present invention relates to a method for washing a washing tub and a washing machine having the same applied thereto, and more particularly, a method for washing a washing tub including a detergent removing step, a laundry amount detecting step, and a soaking step; and a washing machine having the same applied thereto. The method includes a detergent removing step for removing detergent from the washing tub, a washing water supply step for supplying washing water to the washing tub, a laundry amount sensing step for sensing a laundry amount in the washing tub for determining whether the method proceeds to the next step or not, a soaking step for soaking dirt on a surface of the washing tub after applying the washing water to the dirt by moving the washing tub, and a washing step for washing the washing tub, if it is determined in the laundry amount sensing step that the method proceeds to the next step.