Abstract: The loess with high content of contains some sand grains, which often has high liquefaction potential, distributes widely in Loess Plateau and liquefaction is one of the crucial potential earthquake disasters in this region. Using the MTS810Teststar servo soil dynamic triaxial apparatus as test platform, this paper firstly studied the loess saturation by the head saturation method and libration liquefaction test for the saturated loess. Then discuss liquefaction mechanism and liquefaction characteristics of the loess under the continuous cycle dynamic loads, research the loess liquefaction discrimination criterion, analyse the loess liquefaction conditions and the impact factors. In addition, study the growth pattern of dynamic pore water pressure and dynamic strain under the action of the dynamic load of the loess. At the end as it provides the basic theory for the action of loess foundation and loess slope stability research under the effects of earthquake action.