The overall torsion stiffness of the miter gate structure of a large ship lock is very small.Under the action of self-weight,wind pressure and water pressure,the gate is prone to cause excessive distortion during operation.In order to improve the torsional rigidity of miter gate and reduce the deformation of miter gate during operation,the prestress is usually applied to the back-tie rods of miter gate in the design.In this paper,the problem of prestressing force applied to the back-tie rods of the miter gate is analyzed and studied by using the Ansys finite element analysis software,combining the shiplock of the Yakou hydro-junction in Hanjiang River.The analysis results provide reference for the application of the prestress applied to the back-tie rods,and provide reference for the design and calculation of the prestress applied to the back-tie rods of the similar project.