Abstract: Shale gas reservoirs are characterized by developed microfractures and complex pore structures. To study the influences of natural fractures and hydraulic fractures on reservoir pressure during shale gas production, the paper observes dynamic characteristics of reservoir pressure, considers the multi?scale effects of shale gas reservoirs, establishes a mathematical model for seepage flow of shale gas on the basis of the dual media?discrete fracture model, and uses finite element analysis method to obtain numerical solution. The result shows that during shale gas production, reservoir pressure is mainly influenced by fracture amount, aperture and connectivity status. At the early stage of shale gas production, the seepage flow of free gas in fractures is the dominant and reservoir pressure reduces significantly; at the middle and late stages of shale gas production, the adsorbed gas desorbs in the shale gas reservoir, which plays a leading role in the seepage flow, and the reservoir pressure drops slowly