Abstract: In the exploitation process of water - producing gas well,condensation & formation water will gradually move to the well bottom with the pressure decay.The WGR will be raised during production,at the same time underground flow condition will be destroyed,eventually influence well production. In this paper we use gas's non - Darcy flow theory, combine with WGR & gas - water relative permeability curve,via equivalent skin factor to correct deliverability equation & IPR curve.Finally get the forecasting method of productivity in water - producing gas well.Case calculation shows that the revised productivity equation has high prediction accuracy in productivity of water- producing gas well.