Abstract: This paper presents a new method of calculating depth of compressible stratum, in which a viscoelastic-plastic model was adopted. This method with consideration of the variation of deformation modulus of subsoil with the depth and the non-linear relation between stress and deformation is not only suitable for the cohesive soil stratum but also for the cohesionless sandy soil stratum.Besides, in this paper the depth of the compressible stratum measured under field conditions is compared with the values calculated according to various methods. The result of comparison shows that the proposed method is better agreement with practice.