The shale matrix is composed of organic matter and inorganic matter. Methane often adsorbs in organic pores and water adsorbs in inorganic matter. Adsorption layer blocked the spaces of pores, and leads to the decrease of porosity and permeability. However, the influence of adsorption layer on shale permeability is neglected on present research. As a result, the value of calculated Composite Permeability is larger than its true value. Considering the adsorption, slippage and free molecule flow

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... ffects, this paper proposes the organic permeability model, inorganic permeability model and composite permeability model based on capillary calculation model and existing apparent permeability calculation model. In comparison with the experimental results, it is found that the proposed model help to get the reliable results and it is more practical in predicting the shale gas reservoir permeability. Also, the proposed model is used to predict shale permeability of Shan-xi Formation, Paleozoic, Ordos basin, China. The results show that: (1) At the beginning time of development (the pressure is 30MPa), the decreasing of the permeability in organic matter is sensitive when pore diameter is less than 10nm. At the late stage of development (the pressure is 5MPa), the smaller the organic pore diameters are, the greater the permeability in organic matter will increase (2) With the decreasing of pressure and increasing of Langmuir pressure, the increasing rate of permeability increases.(3) with the increasing of water saturation, the damage of inorganic permeability becomes serious.