Abstract: The dynamic deformation properties of lightweight clay-EPS beads soil（LCES） were studied using triaxial apparatus,and the effort was focused on the influence of confining pressure,cement content and EPS content.It was indicated that its dynamic stress-strain curve was of hyperbolic type.The strain of LCES decreased with the increasing confining pressure and the cement content under the same dynamic stress.Under the same dynamic strain,the dynamic secant elastic modulus,Esec of LCES increased and the damping ratio λ decreased with the increasing confining pressure and cement content.Compared with the confining pressure and cement content,there was little effect of EPS content on the dynamic deformation of LCES.The curves of σd–εd,Esec–εd and λ–εd with different EPS contents intersected with each other respectively,and the trend of LCES deformation characteristics was inversely proportional to EPS content near the intersection.The value of dynamic strain at the intersection εint was about 0.5%³.0%,and its magnitude to was related to the mixing proportions and confining pressure.