Abstract: Using the elastic-plastic bounding surface model produced by UMAT of Abaqus, the dynamic simple shear test model of a soil element and the three-dimensional analytical model of seismic compression of sand are established. This paper analyze the earthquake subsidence of sand with different relative densities and clay contents under varied seismic waves. The research shows that, the vertical strain of sand decreased with the increasing clay content in sand when the value of clay content is less than 30%; however, when the value of clay content exceed 30%,the vertical strain become increasing. Besides, a large proportion of site settlement is produced when peak acceleration of earthquake occurred; and for a seismic wave that has several peak accelerations, the vertical strain depends on the value of historical maximum peak acceleration.