Abstract: The detection of water content in the polar regions of the moon is of great significance in scientific research and resource utilization. The Chang 'e-7 mission is scheduled to be launched to the South Pole of the moon in 2026 to explore water ice. The lunar soil volatile matter measuring instrument it carries needs to complete calibration tests before launch. The lunar soil volatile matter measuring instrument consists of four parts including a micro sampling unit. The measurement process includes nine steps such as sampling, transfer, and heating release. There are various errors such as sample weight errors. To ensure measurement accuracy, ground calibration is required: the vacuum specification standard calibrates the pressure output by controlling different temperature points. The calibration of the mass spectrometer is verified for sensitivity by means of the vacuum system and the injection system. The copper hydroxide test can be used to eliminate sampling transfer errors and verify systematic errors. The full-process calibration of water-containing simulated lunar soil simulates the in-orbit environment to verify the full-process error. Through these calibration methods, the randomness and temperature drift of barometric measurement can be constrained, and the residual errors of the system can be corrected, providing methodological support for the inversion of on-orbit data on lunar soil water content.