Abstract: Parallel numerical simulation method for dynamic responses of water conveyance tunnel under seismic excitation is proposed based on ALE (Arbitrary Lagrangian-Eulerian) approach. The ALE is used to deal with the interaction between the inner water and tunnel linings. The proposed coupling load balancing parallel algorithm is applied to accelerate the calculation procedure. The equations are solved using explicit central difference method. For a large-scale water conveyance tunnel, a full three-dimensional water-tunnel-soil coupling simulation model is established and the dynamic responses under non-uniform seismic excitation are analyzed. The actual conditions such as the nonlinear material properties and the nonlinearity of contact and fluid-structure interaction are taken into account. PML (Perfectly Matched Layer) is used to establish the artificial boundaries to represent the infinite domains. This large-scale nonlinear problem is solved on Dawning 5000A supercomputer by using the proposed method. The feasibility for the simulation of the water-tunnel interaction using ALE method is verified through the comparison with the added mass method. The stress and deformation of the water conveyance tunnel under seismic excitation are analyzed. The influences of the inner water and flexible joints on the tunnel's dynamic responses are discussed. The results show that the maximum hoop stress appears at the cross section near the work shaft and the tunnel fulfills the strength requirements. The oval deformation of the tunnel is within the safe range. The tunnel with full inner water bears larger stresses and the flexible joints can reduce the dynamic responses of the tunnel. The proposed parallel method shows better parallel efficiency.