Disclosed are a washing method of a washing machine capable of preventing a phenomenon that remaining detergent is collected into a space where a heater is positioned or a specific space during a washing operation of laundry, capable of minimizing a generation of washing water unnecessarily supplied to the washing machine, and capable of fast heating corresponding laundry before a washing operation for an efficient washing operation, and an apparatus thereof. To this end, the method comprises the steps of: generating steam by heating washing water supplied into a washing machine; injecting the generated steam into laundry inside of a drum of the washing machine; and rotating the drum after injecting the steam into the laundry and thereby washing the laundry.