Abstract: We established flow pattern discrimination method based on GSI by analyzing gas flow pattern discrimination method and analyzed coal gas migration laws of GSI ≥ 45 and GSI <45, the results show that when GSI ≥ 65, bedding / cleats of coal body structure become the controlling factors of gas migration. Two migration modes including diffusion-seepage or seepage occur when starting pressure gradient is over the gas pressure gradient. When GSI = 45 to 65, gas migration laws are similar with the traditional fragmentation coal, it can achieve high-speed linear or non-linear seepage flow (turbulent), internal gas of matrix blocks transport relying on the diffusion. While migration mode for GSI <45 is two poles diffusion.