The dimension of the north anchorage of Taizhou Bridge is 67.9 m long, 52 m wide and 57 m high. The water dredging method was adopted at the beginning of the sinking process. The cost of water dredging method is lower than the un drained dredging method and the efficiency is much higher and more controllable. This method can form good sinking direction to assure the sinking velocity and preciseness, especially suitable for the geological condition of clay and clayey. This paper introduced the water dredging construction method of the super scale caisson based on the north anchorage of Taizhou Bridge.