A dynamic consolidation model of double layered foundation of saturated soil and unsaturated soil is proposed. Mechanism of dynamic compaction treating on double layered foundation is studied by the model. On the base of the mechanism a new technology called soil-mound dynamic consolidation can be applied to treat the ground of saturated silt and silty clay with high groundwater level. The water-pore pressure test, static cone penetration test, settlement plate test are applied to evaluate that of the new technology with different construction parameters. The treatment effect is more remarkable than that of plastic drain-dynamic consolidation.