The flow state of the curved channel is complicated,and the bridge pier is a great change to the flow field of the river,which is very bad for the navigation safety of the ship.In this paper,the three-dimensional turbulent flow field of the pier is simulated by the lattice Boltzmann method,and the three-dimensional turbulence width of the square piers under different flow and bending radius is analyzed by using the large eddy simulation and the motion boundary treatment method.Therefore,the coupling relation between the relative turbulence width and Froude number is established.Based on the above results,the study of Xinxilin Bridge in Sichuan province is carried out and compared with the research results of Changjiang Waterway Planning and Design Institute.The results show that the turbulent flow width of the pier is slightly larger,but the numerical value tends to be reasonable.