Abstract: Because of the ultra-large scale calculation and strong nonlinear calculation of fluid structure interactions (FSIs), the numerical simulation and analysis of water hammer impacts in an ultra-large water conveyance tunnel are difficult. The hybrid modeling method is used to simulate water hammer impacts in an ultra-large water conveyance tunnel. The method can not only yield water hammer simulations along the full tunnel length, but also the detailed structural responses of the segment linings. In the finite element model, the pressure and velocity of fluid field is solved with FLUENT and then applied to the structure as the initial conditions or boundary information. The structural field is solved with the finite-element program LS-DYNA. The interaction between two physical fields is realized using ALE (Arbitrary Lagrangian-Eulerian) description. The structural response of a large-diameter double-line water conveyance tunnel in Shanghai under the impact of water hammer is analyzed. The results presented the propagation of water hammer pressure in the long-distance water conveyance tunnel and the effects on tunnel linings.