A pressure three-dimensional non-uniform loading/unloading and steady pressure model test system has a pressure three-dimensional non-uniform loading/unloading device. The pressure three-dimensional non-uniform loading/unloading device is controlled via an input instruction of the hydraulic loading/unloading and steady pressure automatic control system to carry out pressure three-dimensional gradient non-uniform loading/unloading and steady pressure control. An automatic model displacement test system automatically acquires the displacement of any part inside a test model. A multi-probe peeping system observes a cavern excavation deformation and failure process dynamically in real time.