The construction methods of cofferdam filling, pile foundation holding hoop support and underwater steel box sinking are the most used methods in the construction technology of underwater pier in the new stage. Based on the construction example of the Nanyang anchoring area of the "Three changes to two" project of Jining to Taierzhuang (Jining section) channel of Jinghang Canal, the construction is carried out according to the deep and shallow structure design of the river. Its construction process through reasonable arrangement and rigorous technical management, successfully completed the construction of the water pier, with economic and easy to use, protect the river environment, safe and reliable channel passage and other characteristics, the construction process has been verified by practice, has feasibility and superiority, can be used for reference in the future similar conditions.