Abstract：The model of wave propagation in functionally graded material(FGM) is introduced to soil medium，and the concept of functionally graded soil medium is brought forward. Combined with the actual conditions and test results，exponential functions are used to express the variation of the shear modulus and damping ratio of the soil with the depth. Then，the motion equations for the transmission of the stress wave are derived and solved by using finite difference method. The ground surface response spectra curves of the model are gained under different depths and different soil media. The comparisons and analysis are carried out under a series of circumstances，and some laws of the influences on above structures are obtained，which can provide some references to the antiseismic engineering.
