To improve the wet soft silty sand bearing capacity, vibro-replacement stone column was used. Compared with the practical construction, this paper introduces the vibro-replacement stone column strengthening soft foundation. The principle of the construction, quality control, and inspection technology were discussed. Based on Drucker - Prager elastic-plastic model, different high wet soft foundation was simulated with the numerical analysis software. Results show that vibro-replacement stone column can significantly reduce the roadbed horizontal displacement. The displacement of the subgrade reinforced by stone columns decreases respectively 0.1, 0.2, 0.6, 2.3 cm than the other. If the subgrade is 4 m in height, the displacement reaches 0.2, 0.5, 0.7 cm when the length of stone column is 5, 10, 15m, respectively. To sum up, five - metre long pile is more economic and reasonable.