For studying dynamic response of tailings dam,the seismic response of the 1^＃auxiliary dam of a tailings reservoir was calculated with the Flac3D based on the fully nonlinear dynamic analysis theory,and the acceleration amplification coefficient,dynamic displacement and the dynamic response characteristics of liquefaction in the reservoir were obtained.The results showed that the action of dynamic load led to the dam with acceleration amplification coefficients for the vertical direction and horizontal directions at 1.47 and 2.91 respectively,as well as with more safe reserves.It is shown that little change in the horizontal displacement for the dam and a small percentage of liquefaction,resulting in little impact on the overall stability of the tailings dam.