Model soil design, as a vital component of shaking table test of soil-structure interaction, is introduced briefly. After analyzing drawbacks of existing design methods, the similarity indexes of dynamic characteristic between prototype soil and model soil is derived based on backbone curve equation of dynamic stress-strain of soil. Then, a new approach for model soil design is proposed in which treating the similarity of shear modulus ratio and shear stain with reference strain as controlling factors. Several dynamic triaxial tests are carried out to obtain the - and reference strain of model soil, and the data are compared with those of prototype soil. Then a juding system based on the degree of similarity of - between prototype soil and model soil is proposed. The evaluation indexes of juding system mainly include correlation coefficient, nonuniformity coefficient and coefficient of curvature. The research conclusions have great guiding significance on the design of model soil, which are particularly important for shaking table test.