The accurate measurement of pressure is of great importance to industry process control. In absorption spectroscopy, the spectral line profile and line-width of gas depend on the molecular interactions, temperature, pressure and other factors. The pressure induced line- broadening effect of narrow-band absorption lines of gases can be used for pressure measurement and calibration. A novel pressure gauge calibration method based on cavity ring-down spectroscopy (CRDS) and pressure induced line-broadening effect is presented and experimentally demonstrated at room temperature with a CRDS setup employing a 5.2 μm tunable quantum cascade laser and an absorption line of trace moisture in air near 1 877 cm-1 wavenumber. The measured line-width is 0.084 21 cm-1, and the corresponding pressure is 98.12 kPa, which is in good agreement with a high-precision pressure gauge reading 98.14 kPa. A pressure measurement limit of 0.18 kPa is achieved, estimated from the line-width measurement uncertainty. In addition, the measured pressure broadening coefficient is (0.087 12±0.000 965) cm-1·atm-1, which is in good agreement with the reference value 0.087 1 cm-1·atm-1 given by HITARN database at the same temperature. The proposed method is applied to calibrate a small-scale pressure gauge with sufficient accuracy. The results indicate that high-resolution measurement of absorption line based on CRDS has the potential for high-accuracy pressure measurement and calibration.