The invention provides a test device for a variable gauge wheel set. The test device comprises a base; a power assembly arranged on the base and connected with an axle of a variable gauge wheel set todrive the axle to rotate; a pressure loading assembly arranged on the base and comprising a pressure applying device, wherein the pressure applying device applies pressure to the axle so that the axle can operate under the pressure action of a preset pressure value; an unlocking assembly arranged on the base and comprising an abutting part and a first driving device for driving the abutting partto move, wherein the first driving device drives the abutting part to move towards an unlocking disc of the variable gauge wheel set so as to make contact with the unlocking disc and push the unlocking disc to move to an unlocking position; and the pushing assembly which comprises a second driving device, wherein the second driving device drives the wheels of the variable gauge wheel set to move in the axial direction of the axle so as to adjust the distance between the two wheels. According to the invention, the problem of low precision of the test device for the variable gauge wheel set in the prior art is solved.