The low permeability tight sandstone gas reservoir has poor physical properties and small pore space is easy to generate start-up pressure. However, the gas reservoir’s original seepage way have change because the well have fractured.In this paper, the tight sandstone gas reservoir in western sichuan is taken as the research object, reservoir seepage model and its influence on development effect have simulated by using indoor core experiment and numerical simulation technology, compared the actual production indexes of the gas reservoir.The results show that the tight sandstone gas reservoir that was put into production after fracturing originally changed from changed from a single pore flow into a multistage flow from pore to fracture and from fracture to fracture, and the starting pressure between matrix and matrix and between matrix and fracture greatly affected the development effect. The percolation mode is shown in model 4.The worse the gas reservoir physical property, the greater the influence of starting pressure gradient on the development results.Among them, the permeability less than 0.2×10^-3μm² water saturation greater than 45% is the critical point where the starting pressure gradient has a significant impact on the development effect.The starting pressure gradient in the matrix - fracturing interval has little influence on the development effect, while the starting pressure between the matrix has a great influence on the development effect. The smaller the starting pressure gradient is, the greater the impact range will be. When the starting pressure gradient is less than 4MPa/100m, the recovery factor and formation pressure drop rate can be reduced by up to 40%.