The invention relates to a calibration device for a displacement sensor. The calibration device comprises a base. A displacement sensor mounting seat is fixedly arranged on the base and comprises a bottom wall, a top wall and a connecting wall connected between the bottom wall and the top wall. The bottom wall, the top wall and the connecting wall together form a C-shaped structure with a rightward opening. The bottom wall is provided with a lower clamping structure, and the top wall is provided with an upper clamping structure capable of moving up and down relative to the lower clamping structure. The base is provided with a mechanical micrometer head behind the displacement sensor mounting seat and having an axis extending in the front-rear direction. The measuring end of the measuring rod of the mechanical micrometer head faces the displacement sensor mounting seat. The mechanical micrometer head can be moved and adjusted up and down and can be fixed by a fixing structure after moved and adjusted. The calibration device solves the problem in the prior art that a guide rail sliding seat is required to be installed so as to lead to the complicated structure and the poor universality of the calibration device.