The invention which belongs to the field of civil engineering equipment relates to a full-automatic, digital and large frozen soil direct shear apparatus. The large frozen soil direct shear apparatus which comprises a shear box, a refrigeration system of an upper shear box, a refrigeration system of a lower shear box, a vertical servo loading and monitoring system, a horizontal servo loading and monitoring system, and a measurement and control system is to determine the shear strength of the freeze-thaw interface of the frozen soil or determine the shear strength of full frozen soil and full thawy soil. The size of a frozen soil sample in the embodiment of the invention is 305mm*305mm*200mm, static force and a layered compacting method are adopted to prepare remolded soil samples of different initial water contents and dry densities for shear tests; temperature control systems of the upper shear box and the lower shear box are adjusted to control the temperatures of soils in the shearboxes to guarantee the shear plane to be superposed with the freeze-thaw interface of the frozen soil sample. The direct shear apparatus of the present invention solves problems that the difficulty of testing the shear strength of the freeze-thaw interface is large, the shear tests of coarse grain soil are difficult and the like and provides reasonable design parameters for civil engineering and traffic engineering in cold or highly cold regions.