Abstract: A wind tunnel is a ground test facility that reproduces different flight conditions of aircraft. The precise measurement of wind tunnel instruments is crucial for the safe operation control of wind tunnel equipment and the development and verification of aircraft. In view of the problems such as the need to regularly disassemble pressure instruments for offline measurement, the long calibration cycle, the easy damage of instruments and even the resulting medium leakage, in order to improve the calibration efficiency and safety of on-site pressure instruments of the equipment, the metrologability of wind tunnel pressure instruments is designed based on the idea of in-situ calibration. By analyzing the distribution of on-site pressure instruments of the equipment and the actual pipeline situation, an in-situ calibration scheme for pressure instruments is formulated, and the in-situ calibration method for pressure instruments is determined, including the in-situ calibration method for dispersedly distributed pressure instruments and the in-situ calibration method for centrally distributed pressure instruments. The transformation of the calibration pipeline is completed, and the in-situ calibration standard device is developed, and the in-situ calibration system for wind tunnel pressure instruments is established. To verify the effectiveness of the in-situ calibration method and system, an in-situ calibration test is carried out. The calibration conclusion is compared and verified with the calibration conclusion of a qualified metrological institution, and the consistency of the conclusions is 100%, which has a broad application prospect.