The invention discloses a gravity water drainage assisted oil recovery method and oil recovery system. The method comprises the following steps of: arranging an upper horizontal well at the bottom of the oil zone, arranging a lower horizontal well in parallel below the upper horizontal well, arranging a plurality of production straight wells around the upper horizontal well in the oil zone; respectively arranging steam injecting pipe columns into the upper horizontal well and the plurality of production straight wells for injecting steam, preheating the oil zone with steam, so that the upper horizontal well and the plurality of production straight wells form heat communication; and after the upper horizontal well and the plurality of production straight wells form heat communication, lifting the steam injecting pipe columns from the production straight wells, arranging lift pipe columns into the production straight wells for oil pumping production, and arranging a lift pipe column into the lower horizontal well for draining water and assisting oil pumping. The gravity water drainage assisted oil recovery method and oil recovery system disclosed by the invention can effectively employ a super heavy oil reservoir, thereby reducing the water ratio of the production straight wells and improving the oil recovery rate.