A wind-water power generating system and a method thereof are provided to increase the rotational power of a water wheel through vanes due to wind force even in case the vanes of the water wheel are positioned at the air by installing a vane-rotating device at the vane of the water wheel. A wind-water power generating system comprises: a water wheel(1); a vane installed at a trolley of a rotary body(10) of the water wheel; and a generator installed at the rotary body. The water wheel comprises: an endless track(11); and a rotary body installed at the endless track and made of a plurality of trolleys(12) which are connected to each other. The vane has a shaft coupling device and a vane-rotating device.
