Abstract: In order to study the pore and permeability changes and pore structure characteristics of shale under stress, the porosity and permeability of shale in net confining stress were analyzed through experiment using the shale samples in Zhaotong area, Sichuan Basin.The stress sensitivity of shale reservoir was analyzed by permeability damage rate and stress sensitivity coefficient.The results indicate that the porosity and permeability of shale matrix decrease by a negative exponential function with the increasing effective stress, and permeability is related to pore structure.Shale formation consists of a dual media system including matrix pores and fractures.If the net confing stress is less than 5 MPa, the stress sensitivity coefficient of shale reservoir varies significantly and the shale reservoir is highly sensitive to stress.If the net confing stress is greater than 5 MPa, the stress sensitivity coefficient of the shale reservoir decreases as the effective stress increases slowly, and there is a fluctuation.Stress sensitivity weakens and permeability damage rate increases slowly with the increase of effective stress.It is found that the porosity of different pore sizes decreases with the increase of stress, which reflects the synergistic effect of different pore sizes on porosity in shale, and has certain practical significance to reveal the pore size change of shale reservoir and guide the physical properties of deep shale reservoir.