Considering the changes of pore structure caused by the external force led to significant changes to the permeability of coal.Using the three shaft seepage test,gets the flow of the raw coal specimen through controlled the axial compression and confining pressure constant,solved the nonlinear least squares problem by using the quasi-newton method which gets the initial value by the improved genetic algorithm,then analysis and solves the non-linear seepage laws of the coal.The results show that the the new optimization algorithm can effectively solve the nonlinear least squares problem due to it solves the serious path dependence of the quasi-newton method and needn’t derivation during calculation process,it provides a feasible method to solve the non-linear seepage laws of the coal.Study on nonlinear seepage law of coal body by the method,we found that the permeability coefficient of coal increases with the increase of pore pressure and decreases with the increase of the volume stress,it’s the product of a quadratic function of the pore pressure and the negative exponential function of the volume stress.%考虑到外力引起的孔隙结构改变，将导致煤体渗透性发生显著变化，利用原煤试件的三轴渗透实验数据建立反应瓦斯非线性渗流规律的数学模型，采用基于改进遗传算法赋初值的拟牛顿法求解建立的模型，对瓦斯在原煤试件中的非线性渗流规律进行了求解和分析。结果表明，改进的遗传算法大幅提高了初值寻找的速度和精度，为利用拟牛顿法进行模型最终求解提供保障，从而使得新型优化算法可以有效解决非线性最小二乘问题。采用该方法研究煤体的非线性渗流规律发现，在一定压力范围内，煤体的渗透系数随孔隙压力增加而增加，随体积应力的增加而减小，渗透系数是孔隙压力的二次函数与体积应力的负指数函数的乘积。
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