To address the difficult construction of tall cast-in-place underwater concrete formwork，the low efficiency of underwater formwork disassembly and high safety risk of frequent hoisting，this paper studies the underwater connection，dismantling and hoisting technology of large formwork. T-shaped bolts and three-stage clamping strips are designed for the underwater connection of independent piers，and the underwater mold removal time is shortened to 3-4 hours. A multi-functional combined sling is designed，and the positive and negative rotary connectors are used to realize the release and overall lifting of the underwater formwork top，which improves the construction efficiency，reduces the construction cost and ensures the construction safety. It has reference significance for similar underwater large-scale concrete formwork projects.