The invention relates to the field of underground foundation engineering construction, in particular to a double-water-stop structure of a rotational flow pool outer cylinder constructed through a reverse building method. The double-water-stop structure comprises the rotational flow pool outer cylinder which is formed through multiple times of sectional pouring from top to bottom. The double-water-stop structure is characterized in that annular mortises are formed in the bottoms of upper sections of the outer cylinder, rubber water stop strips are arranged in the mortises, and the bottom faces of the upper sections of the outer cylinder incline upwards; bracket structures are arranged on the outer sides of the crossed parts of the top faces of the lower sections of the outer cylinder and the bottom faces of the upper sections of the outer cylinder. According to the double-water-stop structure, the height difference of concrete is used for compensating for air shrinkage caused in the setting process of the concrete, the concrete in construction seams is made to be dense, and the quality issues such as the water leakage phenomenon are avoided.