Abstract: To ensure the uniformity, accuracy, and reliability of automatic measuring instruments for motor vehicle tyre tread depth, a calibration method is proposed. Firstly, the calibration status both domestically and internationally is introduced, followed by describing the measuring principle for tyre tread depth. The technical scheme of the calibration device is then proposed, and the technical indicators and traceability methods of the calibration device are demonstrated. In addition, through analysis and experimental research on the calibration method, the test results show that the measuring instrument indication error meets MPE: ±0.10 mm, and the calibration method is reasonable and operable. An uncertainty evaluation reveals U = 0.03 mm (k = 2). Finally, a comparison test and data analysis show that the maximum difference modulus of the measured value of the tread depth indication error meets verification requirements, thus verifying the calibration method.