At the middle and high water cut stages of multi-layer sandstone reservoir，the development between layers is uneven，and the interlayer interference is obvious，leading to the great difficulty and low accuracy of productivity prediction for newly drilled adjustment wells. To further analyze the influence of different water cuts on the productivity of multi-layer sandstone reservoirs，this paper constructed the dynamic prediction model of interlayer interference after the variation of interlayer interference coefficients with water cuts was analyzed under different breakthrough coefficients of flow capacity in P Oilfield. The relationship chart of interlayer interference coefficients with the breakthrough coefficients and water cuts was drawn to quantitatively characterize the variation of interlayer interference coefficient with water cuts under different breakthrough coefficients of flow capacity. The productivity formula between productivity index and formation flow coefficient without interlayer interference was constructed to guide the well productivity evaluation of P Oilfield at middle and high water cut stages. The results indicate that the productivity error of new adjustment wells in P Oilfield predicted by interlayer interference correction is 20%，which is lower than that before the correction，indicating a reliable productivity prediction result.