The present invention discloses a non-contact displacement sensor calibrating device used in a high temperature environment. The non-contact displacement sensor calibrating device comprises a pedestal, a sensor base, a position gauge block, a calibration gauge block, a sensor probe and a measurement feeler gauge. The sensor base is connected with the pedestal via a T-shaped groove, the non-contact displacement sensor probe is arranged on the sensor base, and the position gauge block is used to determine the distance between the sensor detection surfaces for carrying out the differential calibration. The calibration gauge block is used to simulate an actually detected surface, the distances between the sensor detection surfaces and the calibration gauge block detected surface are determined by the measurement feeler gauge, after the distances are determined, the sensor base and the calibration gauge block are screwed tightly by the bolts, and then the whole device is placed in a high temperature box to carry out a calibration experiment. The device designed in the present invention can be used for the differential calibration of the non-contact displacement sensors, also can be used for the calibration of the single non-contact displacement sensor, is simple in structure, is simple and convenient to install, and has the characteristic of being convenient to disassemble and assemble under the premise of guaranteeing the measurement precision.