Abstract: It was presented that the caisson construction technique, instability causes and rectification treatment procedure of a swirl pool.It was investigated and analyzed the construction organization, design, construction technique and the actual geological condition of this caisson project according to the instability tilt of the RC swirl pool during its construction, as well as found out the problems of the caisson during construction, and also the causes leading to the instability tilt of the caisson.It was found by the forced analysis of the instable caisson that the center of gravity of the caisson was still within the circle of angle of throat on the bottom of the caisson.In order to ensure the position of the rectified caisson to be basically the same as that of its original design, the rectification scheme was determined, i.e.the caisson would go back gradually to its correct position by relying on self-weight and limit constraints resulting from erecting piles and reaction platform respectively in the southeast and northwest corners of the caisson as well as by imbalance excavation．