Abstract: The horizontal well technology has good foreground in oil and gas development.At present horizontal well has been applied in low permeable gas field,so the research of horizontal well off-take potential has great significance in improving the efficiency of exploitation.According to the gas flow model in reservoir and the flow model in horizontal well tube,the coupling flow model of reservoir-horizontal well tube is built.The reciprocity and the effect of the two flows are considered.The paper uses unsteady state model in gas reservoir and considers the anisotropy in reservoir and the non-Darcy flow of gas.Pseudo-pressure is used in the calculation.