Abstract: According to the obvious creep characteristics of soft soils, the Cvisc viswelasto-plasticmode of FLAC^3D is employed to simulate subgrade settlement after construction, and the displacements with creep and no-creep are compared. The calculated results show that the displacement reaches 16 cm after 20 years' creep, and it is only 4 cm under no creep. The creep settlement is more half of the all. The course of creep is the process of gradual consolidtion. The creep effect makes the displacement continue to settle. To prevent the adjective settlement, CFG pile treatment (cement fly-ash piles) is performed for the subgrade. By changing the different pile parameters (pile length, elastic modulus), it is found that the influence of the pile length is greater than that of the elastic modulus. The piles and cushions have obvious influence on plastic zone. The destructive zone is gathered near the cushion, and soil mass failure and plastic zone are enormously reduced.