Abstract: Discusses the relationships between stress and strain, dynamic modulus and dynamic strain and the degree ratio of liquefaction to stress and number of cycles of destructive vibration in view of the fly ash consolidation with liquid drained (CD) and undrained (CU) to which the triaxial tests of fly ash samples taken from a stack yard of a petrochemical plant were done statically and dynamically. The finite element software ANSYS was applied to the static analysis of the heightened ash stacked dam and the dynamic response of a tailing dam under the action of Park Field seismic wave. A liquefaction analysis was made to the ash stack yard by way of shear stress correlation. The results showed that the relative density of fly ash (Dr) affects greatly the area of liquefaction region, i.e. the smaller the Dr the bigger the area. A conclusion is drawn that the control of Dr is indispensable to the liquefaction stability of ash stacked dam.