The invention discloses a transmission switching apparatus. The apparatus comprises a casing, a first rotating shaft, a second rotating shaft and a belt wheel transmission mechanism. The first rotating shaft and the second rotating shaft are both rotationally installed on the casing, the first rotating shaft and the second rotating shaft are parallel to each other, and the first rotating shaft is disposed below the second rotating shaft; the first rotating shaft and the second rotating shaft are connected through the belt wheel transmission mechanism; and the casing is respectively provided with a first power source installation through hole and a second power source installation through hole at positions opposite to the first rotating shaft and the second rotating shaft, for selecting to install a power source at the first power source installation through hole or the second power source installation through hole and accordingly driving the first rotating shaft to rotate through the power source. According to the invention, the function scope of a test platform of a machine tool is greatly expanded, the system structure and the adjustment switching operation of the test platform are simplified, the weight and the dimension of the whole test platform are reduced, and a guarantee is provided for rapid and convenient conduction of experimental research.