The invention provides a testing apparatus used for simulating foundation pit three-dimensional seepage caused by combined effects of separating-lowering-pouring and ground deformation mechanism. The testing apparatus is used for solving a problem of lack of experiment equipment, which is used for simulating foundation pit three-dimensional seepage caused by combined effects of separating-lowering-pouring and ground deformation mechanism, and systematic researches on relating data and mechanism at present. The testing apparatus comprises a model casing, geotextile, permeable steel plates, underground diaphragm walls, a pumping well, a recharge well, measuring devices and data collecting devices. The model casing is divided into a water zone, a soil zone and a foundation pit zone; the measuring devices comprise a flowmeter, a stratum displacement meter, a water manometer, a contact electric displacement meter, a pore water pressure gauge, and the like, and is capable of realizing accurate measurement on flow displacement pressure; and the data collecting devices are connected with the measuring devices. The testing apparatus is capable of realizing researches on the mechanism of pumping depression cone and recharge lifting underground water level three-dimensional seepage effects, and the relationship between ground deformation and groundwater table fluctuation.