Displacement test device

A displacement test device comprises a first transmission wheel, a second transmission wheel, a transmission rope, an encoder, two limiting parts and a connecting part. The transmission rope is sleeved on the first transmission wheel and the second transmission wheel, and forms an enclosed loop structure. The rotation direction of the first transmission wheel is the same as the transmission direction of the second transmission wheel. The encoder is rotationally connected with the firs transmission wheel. The two limiting parts are both fixed to the transmission rope. The connecting part is connected with the transmission rope, and two sides of the connecting part are pressed against the two limiting parts. The displacement test device prevents errors caused by changes of a winding diameter during a winding process, and thus the test precision and accuracy of the displacement test device are improved. Also, a problem that a conventional displacement test device is not suitable for a long stroke due to limitation of winding turns is solved. In addition, the displacement test device is characterized by simple structure, low cost, small profile dimension, firm integral structure, etc.