Abstract: First of all, based on corresponding relations among the pressure, density and time under normal-consolidated states of clay, influence of structural character on consolidated state and mechanical properties of clay, and the different mechanism forming true preconsolidation pressure and structural yield pressure, this paper proposes a new method of identification for the consolidated types of clays. The consolidated states of clays are divided into six types, i. e. under-consolidated, normal-consolidated and over-consolidated clays, and those with structural strength.Then, the influence of consolidated states and structural strength on the lateral pressure coefficient （K0） under condition of no lateral deformation is discussed. As opposed to above, the consolidated types of clays can be identified by varied law of the coefficient. The advantage and existing problems of this method are poinded out.Finally, the method of distinguishing between causes of overconsolidation by loading and secondary consolidation is provided.