Abstract：In order to study the nanoscale pore structure characteristics of different rank coal body structure,low-temperature nitrogen adsorption method was used to make contrast experiment on eight groups of coal samples which came from Suzhou Zouzhuang mine,Pingdingshan 8th mine and Hebi 9th mine,then the characteristics of coal pore structure were analyzed successfully; meanwhile,by using pore FHH model basis of fractal geometry theory,the impact was revealed on the coal pore structure difference of the coal metamorphic degree and extent of damage. The results show that:( 1) for different metamorphic degree of coal,the link of adsorption capacity and metamorphic degree is not a linear relationship; compared with the symbiotic native structure of coal,the average aperture of tectonic coal is generally small,but the pore specific surface area is larger,and the adsorption capacity of tectonic coal is significantly stronger than the original structure of coal.( 2) for different rank coal,its fractal dimension D of doesn't increase linearly with the degree of coalification; tectonic deformation effect prompts tectonic coal pore structure to be more complicated.( 3) the bigger fractal dimension D is,the more complex the pore structure of coal shows,and the greater the coal pore specific surface area and adsorption capacity.( 4) fractal dimension is inversely proportional with the average pore diameter.

Keyword：nano-scale pore structural;the low temperature liquid nitrogen adsorption;tectonic coal;fractal dimension;