As a kind of low permeability reservoir, fluid solid coupling effect is obvious in shale gas reservoir exploitation. Based on seepage flow mechanics and Biot consolidation theory, considering the starting pressure gradient of shale gas reservoir, and desorption of shale gas, a coupling mathematical model was established,which was suitable to all gas flow type (continuous flow, slip flow, transition flow, molecular collision) in shale pore. The mathematical model including the interaction of shale gas seepage and deformation, and must be solved by coupling. The numerical solution was gotten by program composition based on explicit iteration. The calculation results showed that the impact on pressure is obvious considering and not considering fluid solid coupling, pressure decreasing trend in fluid solid coupling is faster than that without considering coupling case, which fit reality more. Fluid solid coupling phenomenon, effect shale gas seepage greatly, must be considered in shale gas exploitation.