Abstract: In this paper, the effect of gas slippage in low permeation gas reservoirs is researched. Firstly, as the phenomenon of gas slippage has effected to the rate of permeation in gas measure, the mathematical model of nonlinear parabolic partial differential equation which reflects the rule of low permeation porous medium gas permeance is built according to the effect. Then the well posed of the solution to the nonlinear partial differential equation model in the condition of nonlinear boundary is analyzed in mathematical way. We also theoretically prove the existence, unique and stability of the solution to the model. Those results build the foundation for numerical calculation.