The invention relates to a device for rock mechanics direct shear test, in particular to an acoustic emission test device for the rock mechanics direct shear process, in order to solve the problem that damaged microstructure and energy loss of rock cannot be analyzed as an existing rock mechanics direct shear tester does not perform acoustic emission test. The acoustic emission test device mainly comprises an upper pressure head, a base, a horizontal pressure head, a lower shear box, a shear ring, a test piece, a force transmission iron briquette, an upper shear box, sensors and the like, and is characterized in that the upper pressure head and the horizontal pressure head load normal and horizontal force respectively, the lower shear box is placed on the base, the test piece can be placed in the shear ring inside the lower shear box, the force transmission iron briquette is arranged in the upper shear box, and the sensors contact with the test piece through slots inside the upper shear box, the lower shear box and the shear ring. Thus, when a tester performs shear test according to structural features thereof, a time-varying correlation diagram about impact number, shear force, energy accumulation and the like is created via the acoustic emission test device, and strength and property of the test piece can be known from microstructure.