The new-type structure of "three towers of two-span" suspension bridge with the main span of 2×1080m is put to use in Taizhou Bridge. The foundation of Middle Tower adopts an extra-large underwater caisson structure with the three dimension size about 58m×44m×76m, which has been so far the deepest underwater caisson in the world. The caisson is divided into two sections, that is, Steel Caisson on the bottom and Concrete Caisson on the top. The underwater positioning, landing of Steel Caisson and the height addition construction of Concrete Caisson are of great construction difficulties and thus brought high safety risk. In this paper, Taking Taizhou Bridge as background, the safety control technology and management of underwater caisson construction is presented, which can play a good reference for similar projects.