In order to study the vibration response of the ballastless track and subgrade to high-speed train，the finite element method was used to established a full-scale 3D subgrade model in the time domain. The dynamic stress level of each layer of the subgrade，and the amplitude of variation at the direction of vertical and horizontal were analyzed. The modeling results were compared with the measured data of the Wu-guang and Sui-yu railway lines. The results show that，in the vertical direction，the dynamic stress of the subgrade of modeling is slightly higher than that of the measured data，and the attenuation value of the top surface of the foundation is almost identical，the value at the position of z=0.4 m，2.7 m and 4.7 m is 95%，47% and 30%，respectively. And the final attenuation value of the model test is relatively high. The dynamic stress surface of the subgrade is distributed in a saddle-shape along the line transversely. The difference between the center and the edge of the support layer is obvious. The distribution characteristic gradually change to the high in the middle and low on both sides with the increase of depth. And the value attenuated to both sides of the line. The dynamic stress of the subgrade is characterized by the obvious of the Gauss along the longitudinal direction，and the amplitude of the vertical dynamic stress of each layer of the subgrade is basically attenuating along the y direction of the line. The load at the edge of the track slab is reduced to the 13%～16% of that at the center of the track.