Abstract: The gates of ship lock undergo considerable torsional deformation whilecarrying the loads of water pressure, deadweight etc. To fix tied-rodson the back of the gates is one of the measures to resist thedeformation.In this paper, based on the experiments to prestress thetied-rods on the gates of the ship lock in the Three Gorges project, theconditions how to control prestress are obtained by means of anoptimized model of prestress. The failure of the traditionaltwisting-moment-method is analyzed. Thus, a technological procedure toprestress the tied-rods on the back of the gates without twisting-momentis proposed, together with a series of new technologies, such as to makemain tied-rods in tension only. These new technologies improve theconstruction quantity, the accuracy of installing the gates of ship lockin the Three Gorges project.