Abstract: In order to find out the difference of pore characteristics of medium rank coal with different degrees of destruction, the low temperature liquid nitrogen method was used to test coal samples with different degrees of destruction in Pingdingshan No.4 mine, and the difference of pore structure, distribution, fractal characteristics and adsorption performance were obtained by comparative analysis. The results showed that the adsorption equilibrium isotherm of cataclastic coal and fragmented coal were type III, and the macropores were developed. Mylonite coal was type IV with high mesoporous content. The greater the degree of coal destruction is, the greater the total pore volume and specific surface area is, the more complex the internal pore structure is, and the greater the nitrogen adsorption capacity is. The nitrogen adsorption capacity of 2-4 nm pores was mainly controlled by the specific surface area, while the pore diameter of more than 4 nm was mainly controlled by the pore volume.