Based on the shaking table model tests of a shallow-buried and bias double-arched tunnel with and without foam concrete damping layer whose geometric similarity ratio is 1:20, the influence of foam concrete damping layer on the acceleration and strain of the tunnel lining was studied, and the seismic reduction effects and mechanism of foam concrete damping layer were discussed. The research conclusion is as follows. (1)The damping layer significantly reduces the acceleration response of the left arch of double-arched tunnel, but significantly increases the acceleration response of the right arch. The foam concrete damping layer does not change the main frequency range of acceleration response. (2)In addition to reducing the horizontal acceleration of the left arch foot and left arch crown of the left tunnel, the foam concrete damping layer has a significant amplification effect on other measuring points of the tunnel, especially the right tunnel, which makes the horizontal acceleration "free surface effect" on the bias side significantly increase. The vertical acceleration of the left tunnel is mainly reduced by the foam concrete damping layer. For the right tunnel, except for the left and right arch feet, the vertical acceleration is reduced, and the other locations are significantly enlarged, which is related to the biased stress environment of tunnel. The thickness of the overlying rock and soil layer on the eccentric pressure side of the right tunnel should be strictly controlled. (3)The foam concrete damping layer will not change the rule that the strain in the cross section direction of the corresponding position of the tunnel lining is significantly greater than the strain in the longitudinal direction; The foam concrete damping layer can significantly reduce the strain in cross section direction and longitudinal direction, but the reduction effect is different, which is related to the location. (4)The influence of foam concrete damping layer on the strain of tunnel lining is significantly different from that on the acceleration, and there is no amplification of the "free surface effect" of strain. In addition to the individual excitation strength at individual locations, the foam concrete damping layer has the effect of significantly reducing the main strain of the lining. There is a law that the greater the excitation strength, the smaller the strain reduction effect. The strain response of the left arch waist, right arch shoulder, and right arch shoulder of the tunnel under earthquake conditions is very complex and should be given special attention. (5)The refraction and reflection of seismic waves in the pores of the foam concrete damping layer dissipate seismic energy. The larger deformation capacity of the foam concrete damping layer can absorb seismic energy, so that it has a damping effect. However, the specific damping effect is closely related to the stress environment of the lining location and the propagation characteristics of seismic waves. The research results can? provide some reference for the research and application of foam concrete damping layer.