Abstract: In order to research the reinforcement effect of soft soil foundation by dynamic consolidation, the section of Suxin expressway with typical geological conditions was chosen to carry out dynamic consolidation field test of soft soil foundation treatment based on dynamic replacement method. No gravel layer, 20 cm gravel layer and 40 cm gravel layer were used to conduct the field test in different test point. The dissipation of pore water pressure with time was observed and analyzed during the test. The test results show that during the dynamic compaction, excess pore water pressure increases and then decreases. The peak time is in relation to the time of dynamic compact. The increasing of the soil strength for the thick gravel layers is relatively obvious. And the improvement of soil strength is remarkable by comparing the physical and mechanical parameters The results indicate that although the dynamic consolidation destroys original structure of soil, its strength is improved and reinforcement effect is obvious.