In recent decades, the stress sensitivity of tight sandstone reservoirs has attracted wide attention from scholars. Due to the different mineral composition and diagenesis of tight sandstone reservoirs, the permeability stress sensitivity of tight sandstone cores is different from that of ordinary rock matrixes, and the existing stress sensitivity models are not applicable. In response to this problem, this paper derives a modified power-law permeability model to evaluate the permeability stress sensitivity of tight sandstone reservoirs, and uses two parameters ηeff and η′eff to describe the stress sensitivity. The research team separately studied a tight sandstone reservoir and a tight sandstone reservoir in the Ordos Basin. For coring in a gas reservoir, the coring direction includes horizontal bedding and vertical bedding. We use the pressure pulse decay method to carry out the permeability stress sensitivity experiment. The results show that compared with tight sandstone gas reservoirs, the initial permeability and permeability disappearing stress of tight sandstone reservoirs are both higher, indicating a lower flow resistance of tight sandstone reservoirs. In different directions, the permeability in the horizontal bedding direction is 2 to 3 times that of the vertical bedding direction. This paper also compares the parameters ηeff and η′eff of the stress sensitivity model of tight sandstone reservoirs, and derives their ranges from experimental data through regression analysis. The results show that ηeff and η′eff have a more significant influence on the fitting than a single parameter. This revised model is helpful for the improvement of the reservoir simulator and the accurate prediction of oil and gas production in tight sandstone.