Abstract: To investigate the pressure-relief effect on underlying coal seams after long-distance coal seam mining, this study takes the No. 7 coal mining face and the underlying No. 12 and No. 13 coal seams at Hongyang No. 3 Mine as the research objects. The No. 7 coal seam is 65 m above the No. 12 coal seam, and the spacing between the No. 12 and No. 13 coal seams ranges from 0 to 1 m (they can be regarded as a single coal seam). Using the gas component analysis method, gas samples from the No. 7 coal seam (coalbed methane), mixed gas samples from the goaf, and mixed gas samples from the No. 12 and No. 13 coal seams were collected separately and sent to the laboratory for testing the contents of CO₂, O₂, N₂, CH₄, C₂H₆ and other hydrocarbon compounds. Through data screening and analysis, it was found that in the methane (CH₄) of the goaf gas samples, the contribution from the No. 12 and No. 13 coal seams accounts for 0.99%～4.8%, while that from the No. 7 coal seam accounts for 95.2%～99.01%, indicating that under the influence of mining, part of the gas from the No. 12 and No. 13 coal seams migrated into the goaf. The gas component analysis method adopted in this study can provide a new technical means for stratified metering in combined extraction of coal seam groups and for source analysis of gas emissions.