The total quantity of concrete exceeds 30 000 m³ for the north anchor caisson of Taizhou Bridge, which is the largest quantity underwater concrete for bottom sealing construction till now in China, and its construction is quite difficult with high requirements for site organization. This article presents the bottom sealing construction technology for the caisson of north anchor of Taizhou Bridge mainly in the aspects of base cleaning, bottom sealing equipment arrangement and sealing concrete construction technique.