Abstract: The three-dimensional finite difference program FLAC^3D (Fast Lagrangian Analysis of Continua) is used to establish the model of the improved foundation soil by cement piles and to analyze seismic response. From the point of the numerical analysis, it adopts a visualized way to make a systematic analysis about the vertical displacement, the excess pore water pressure, the pore pressure ratio, the shear strain increment, the shear stress on interface elements and the surface acceleration. It helps us to obtain some valuable conclusions by summarizing the changing patterns of above parameters. It has definite instruct meaning for practical projects in the future.