The invention discloses a test device capable of simulating basement bottom plate stress under an effect of pressure water and a use method thereof. The test device comprises a water storage tank, a first water pump, a second water pump, a first check valve, a second check valve, a surge tank, a relief valve, a water pressure sensor, a filter, a foundation pit model case, a pipeline, a basement model and a measurement system. The test device is capable of simulating basement bottom plate stress under an effect of pressure water and can be used for simulating stress conditions of a basement bottom plate under a condition of constant or changing top load of a building below a fixed artesian head, researching the sizes and distribution rules of subgrade reaction and water buoyancy suffered by the basement bottom plate and providing an effective data support for theoretical analysis. The test device is capable of providing high stable water level and simulating the effect of high artesian head; furthermore, since the two water pumps are not needed to operate all the time and can supplement each other and coordinate with each other in operation, so that losses of each water pump are less, the failure rate is reduced, and energy conservation and environmental protection are achieved.