Abstract: This article focuses on gas flow regularity in nano-micron porous media. The flow state was judged by Knudsen number, and then the flow state chart was drawn. The flow characteristics were illustrated for different regions. The correction coefficient of permeability was improved based on the Beskok-Karniadakis model. By introducing polynomial correction coefficients, the Beskok-Karniadakis model was simplified to a binomial equation, and the values of polynomial correction coefficients were obtained by the least squares method. Compared with the Beskok-Karniadakis model, the simplified model has high accuracy. The flow rate equation in nano-micron porous media was developed based on the simplified model. The gas unidirectional seepage law was derived from indoor micro seepage experiment. The flow rate equation in nano-micron porous media agrees with experimental data. Factors influencing the gas flow rate were numerically studied by programming on the base of this model. It is found that the gas flow rate increases more and more quickly with the pressure square difference, and increases with the permeability of porous media and the Knudsen diffusion coefficient.