Abstract: Material characteristics of frozen soil is studied from the viewpoint of meso-mechanics mechanism of composite materials,where the equivalent elastic constants of the frozen soil are obtained by use of the law of mixtures,and the elastic constitutive model of the frozen soil set up using these constants.Based on this constitutive model,stress-strain curves of the frozen sand-soil with different volumetric percentage of ice at different temperatures are calculated.The results look highly consistent with the experimental data,which indicates that this model can well describe the mechanical characters of frozen soil.