Abstract: Aiming at the situation of different gas occurrence status in a mine which belongs to Kaiping syncline wings in the same tectonic unit, profile analysis, fault analysis, groundwater dynamic analysis are used to reveal the root causes of gas occurrence difference from the aspects of geological structure and hydrogeological condition. The results show that asymmetric syncline controlled gas structure, angle upright, even reverse wing compressional reverse faults growth, gas sealing conditions of coal seam can be strengthened, coalbed methane content is far better than the gentle dip angle wing; "larege water and little gas" is a basic law of gas geology; gas and groundwater flowing in the same direction of coal seam will form the relatively poor gas area. Taking Kaiping syncline axis as the boundary, there are great differences in the southeast wing and northwest wing of geological structure and hydrogeological condition, which results in different characteristics and distribution laws of mine gas occurrence.