Tight sandstone reservoirs have poor physical properties and complex pore structures，so hydraulic fracturing technology is usually used to improve the beneficial development of tight sandstone reservoirs. However，the permeability of tight sandstone shows significant nonlinear characteristics with the change in effective stress，and the TERZAGHI linear effective stress theory is no longer suitable for evaluating the relationship between permeability and effective stress in tight sandstone due to the combined action of the complex fracture network formed after hydraulic fracturing and proppant. In order to determine the effective stress and stress sensitivity of tight sandstone，this paper studies the tight sandstone samples from Xujiahe Formation in the southern part of Sichuan Basin and carries out the stress sensitivity experiments for rock samples with matrix，natural fractures，and artificial fractures under three different confining pressures. The results show that during the aging test of tight sandstone，the permeability damage rates of rock samples with matrix，natural fractures，and artificial fractures without proppant increase successively，and the recovery rates of permeability decrease successively. For rock samples with artificial fractures，the proppant filling effectively increases the permeability，with the maximum permeability achieved at 25% proppant filling，which reduces the permeability damage rate of the rock samples. Compared with those of the rock samples with matrix and natural fractures，the non-linear characteristics of permeability contours of the rock samples with artificial fractures are more obvious. The non-linear effective stress coefficients of the rock samples are calculated by the response-surface model，and the variation range of non-linear effective stress coefficients is the widest in the proppant-filled rock samples with artificial fractures，followed by the rock samples with natural fractures，and the rock samples with the matrix come last. Finally，the effective stress calculated by the non-linear effective stress coefficient produces a good correlation with the permeability.