Abstract: This paper has discussed the coupling theory of migration and seepage field of long vertical distance coal seam group in mining conditions and the variation characteristics of displacement field and gas pressure field and has established the overlying rock stress distribution and multi-physics coupling model of gas migration. Based on the numerical analysis software FLAC3D, the paper has done finite element solution of the mathematical model. In addition, the research has also analyzed the coal seam gas seepage distribution characteristics of Fengfeng Group No.2 and No.4 coal seam during mining, the strata displacement characteristics and the strata stress distribution rules under mining conditions. The engineering verification has shown that: The pressure relief effect is obvious of No.4 coal mine upon the upper part of No.2 coal mine; the actual relief range is larger than that defined by the reference pressure-relief angle on the basis of coal and gas outburst prevention regulations; the gas release field is large, and gas drainage of No.2 coal 172102，172104 working face has an obvious effect, whose drainage rate has reached 33.12% and 46.59% respectively, thus can help to eliminate the outburst danger．

Key words: coal seam group, coupling mechanism, mathematical model, seepage field, pressure-relief angle, drainage rate