The invention discloses a testing apparatus capable of simulating soil under effect of dynamic confined water and a method thereof. The testing apparatus comprises a main cylinder, a data acquisitioninstrument, a vacuum pump, and a confined water pressure control system; the confined water pressure control system comprises a synthetic glass cylinder apparatus, a flowmeter, and an electronic valve; the main cylinder comprises a cover plate, a top cylinder, several middle cylinders, a bottom cylinder, and a dolly; and aperture water pressure gauge fixing devices are arranged at different heightpositions of the main cylinder. The testing apparatus can simulate a dynamic and continuous change process of confined water in foundation, the water and soil pressure as well as deformation of the foundation under effect of the dynamic confined water are measured and calculated, the relative test data is arranged, the problems of bearing and deformation development rules of the foundation are determined; the influence of a mean value, an amplitude and rate of the change of the dynamic confined water on stability of the foundation can be researched, the effective test data support can be provided for research of the foundation problems due to effect of the dynamic confined water, and the basis can be provided for a theoretical analysis model at a later period.