Abstract: A gas source based soil pressure box calibration device was designed for the calibration method of soil pressure boxes. Calibration tests were conducted on soil pressure boxes with ranges of 0.1 MPa and 2.0 MPa, and compared with the oil pressure calibration method given by the manufacturer. The nonlinear error, repeatability error, and hysteresis error obtained by the two calibration methods were analyzed. The relationship between pressure and frequency is linearly fitted using the least squares method to obtain the calibration coefficient K value. The results indicate that the pressure calibration device is stable and reliable, with high pressure control accuracy and accurate and effective experimental data. The repeatability of the pressure calibration method is better than that of the oil pressure calibration method, and the loading curve is more linear. This device provides a new method for precise calibration of soil pressure boxes, which has important practical significance for obtaining more accurate pressure values during the calibration process of soil pressure boxes.