Abstract: ion As the hazard of sand seismic liquefaction is random, a probability method for assessing the hazard is proposed, that is, non-liquefaction, light liquefaction, middling liquefaction, and serious liquefaction are quantified with probability. The expressions to compute the liquefaction hazard probability are also proposed by the method of Monte Carlo. A case is analyzed by the probability method and the result shows that the probability method can quantitatively assess the liquefaction hazard.