The invention provides a self-balancing type coal rock triaxial loading seepage and displacement test instrument and method. The instrument comprises a triaxial test module used for providing a closedspace and a seepage test space for triaxial loading of a coal rock sample, a pressure loading module used for loading and controlling axial and circumferential pressures of the sample, a fluid injection module used for pressurizing gas/water and injecting the gas/water into the test space, and a data collecting module used for acquiring test data of axial and circumferential deformation of the sample, gas pressure, mass flow, component concentration and the like. The seepage rate and the displacement effect of the coal rock sample under a quasi-static or dynamic load can be measured; the operation is convenient; and the data acquisition is accurate.