Shale gas reservoir has drastically low permeability and production capacity，and thus it can only be exploited after simulated reservoir volume fracturing in order to form fracture network. Traditionally，dual porosity model is the most common method for numerical simulation，however，it becomes inefficient when facing the natural fractures far away from well which open and connect with each other after volume fracturing. In order to describe the actual flow situation and the adsorption mechanism of gas of fractured shale gas reservoir，a triple porosity-dual permeability model was built. The new model considers the adsorption mechanism of shale gas and takes the matrix as gas source，and the first-degree and second-degree secondary fractures were regarded as two equivalent porous continuums while the main fractures were described explicitly as discrete fractures. A comparison between results of the new triple porous model and the traditional dual medium model was conducted. The gas production rate and cumulative production rate of the new triple porous model are both higher than those of the traditional dual medium model. Considering the rule that observed gas production rate is always higher than that of traditional dual medium model，the simulation result of the new triple porous model is more accurate. The analysis result shows that the permeability of second-degree secondary fractures has great influence on cumulative production rate and should be improved by measures in the production，while the influence of initial adsorbed gas content is not obvious.