Abstract: In order to grasp the gas distribution law in the No.3 coal seam of Qianhe Coal Mine,according to the geological structure characteristics and coal seams occurrence situation of this mine,the gas distribution law in the No.3 coal seam is studied through on-site measurement of the coal seam original gas content,original gas pressure,and laboratory measurement of gas component content,combined with the theory of vertical zoning of coal seam gas.The research results indicate that the gas content in the No.3 coal seam of Qianhe Coal Mine is relatively low,with a maximum measured gas content of 4.60 m~3/t;The original gas pressure and CH₄ component content are relatively low,with a maximum measured gas pressure of 0.22 MPa and a CH₄ component content of 70.07%;Affected by the large area of coal seam hidden outcrops in the eastern part of the well field,it is determined that the No.3 coal seam of Qianhe Coal Mine is located in the N₂-CH₄ zone of the gas weathered zone;In this zone,the occurrence of coal seam gas is uneven,and the regularity between gas content,gas pressure,and coal seam burial depth is not obvious.This study provides a reference for predicting the amount of mine gas emissions and selecting reasonable extraction methods.