In the construction of flood discharge gates, due to the large slope of the bracket and the fact that the entire structural contour line is a permanent surface, the concrete surface smoothness is required to be high. Therefore, it is very difficult in actual construction, and high requirements are placed on steel bars, formwork, and load-bearing structures. In order to reduce the safety risks of the construction of the bracket section and accelerate the construction progress while ensuring quality, internal tension steel truss prefabricated concrete formwork is selected as the bracket formwork for the flood discharge and sand flushing gate pier. To ensure the safety and stability of the bracket truss structure upstream and downstream of the gate pier, a bracket structure verification calculation was carried out. Through research and practice, it has been proven that the construction technology of prefabricated concrete formwork with internal tension steel truss improves work efficiency, reduces construction safety risks, and has reliable appearance and forming quality, meeting the construction requirements of gate pier brackets. It can be promoted and used in similar projects.