Abstract: Take the preconstruction part of Guangle highway for an example, two plane strain finite element models of natural soft clay foundation and the foundation reinforced by pipe pile are established. With the analysis of construction stage, displacement field and stress field in the two models are obtained at each stage of the embankment construction process. Then comparative analysis between the two models can reveal the mechanism of reinforcement in a soft clay foundation provided by pipe pile. Results show that the integrality of soft clay foundation improves greatly after the application of pipe pile which takes big part of upper load, making soil taking less and then reducing the foundation deformation. In addition, around the center of the embankment, soil stress and deformation are larger than other areas. It is better to encrypt piles in this area and less in other areas from an economic point of view.