Abstract: In this paper an analysis of the criteria for evaluating soil liquefaction potential i. e., criteria of limit equilibrium and initial liquefaction is given,and it is pointed out that they are two qualitatively different limits and the latter is better with respect to liquefaction criteria.Since there are some main defects in the current stress analysis method for evaluating soil liquefaction potential, the energy analysis procedure is proposed and its simplified method is also given here in order to have a simple rapid evaluation.Finally, the delineation of boundary between zones of liquefaction and no liquefaction in the Niigata earthquake of June 16,1964,is determined by the simplified method of energy analysis. It may be seen that the boundary determined in this way is in reasonably good agreement with the boundaries determined by Kishda and Koizumi on the basis of field observation and Seed's simplified procedure.