Based on the actual project in Dalian， this paper studies the dynamic interaction （SSSI） of the double tunnel sand bridge pile system under earthquake through shaking table test， obtains the dynamic response law of structure and site， and compares it with ABAQUS numerical simulation. The Kelvin constitutive model subroutine is introduced into the numerical model， and the equivalent linear method is used to deal with the nonlinear problem of sand in the calculation process. The experimental results are compared with the numerical model to verify the reliability of the numerical simulation. On this basis， eight working conditions are designed， and the interaction law between structures in the system is studied through comparative analysis. The results show that the tunnel will amplify the peak acceleration of the bridge pile and adjacent tunnel， but the bridge pile will weaken the peak accelera? tion of the side tunnel； the existence of the tunnel and bridge pile will increase each other's section shear force and bending moment. The main affected areas are concentrated in the upper and lower arches of the tunnel and the interface between the pile bottom of the bridge pile and the pile-soil.