Abstract: Based on abundant geological data, the cleat, adsorption, pore volume, gas-bearing property and ash productivity of Permo-Carboniferous coal in North China have been studied systematically in this paper,and the relationship of coal lithology to the physical behavior of coal seam gas reservoirs has been established. It is suggested that coal lithological types with high content vitrinites have better physical behavior conditions for coal seam gas accumulation. The coal beds of Carboniferous and Permian Taiyuan and Shanxi Formations in North China have relatively worse coal lithological types in the North and the South.The central part has the best coal lithological type and is a favourable region for the physical behavior conditions of coal seam gas reservoirs.