Provided is a washing method of a washing machine including an outer tub for receiving washing water, an inner tub rotatably provided in the outer tub to receive laundry, a pulsator rotatably provided in the inner tub, and a motor providing driving force to rotate at least one of the inner tub and the pulsator. In the washing method, a first centrifugal circulation water stream is formed by rotating the inner tub such that the washing water rises along a space between the outer and inner tubs and falls into the inner tub. An agitating water stream is formed by rotating the pulsator rotating the washing water. Here, the forming of the agitating water stream includes forming a first agitating water stream by controlling the motor with a first net acting ratio, and forming a second agitating water stream by controlling the motor with a second net acting ratio lower than the first net acting ratio.