Abstract: In order to study the pore structure characteristics of different macerals in low-rank coal, a floatation experiment was conducted to separate different macerals from raw coal samples which were selected from No.42 coal seam of Xinjiang Fukang Coal Mine and No.8+9 coal seam of Xiegou Coal Mine in the east area of Hubei Province, then the specific surface, pore volume, pore size and other parameters for two kinds of raw coal and different macerals were tested by low termperature liguid nitrogen adsorption experiment, and their adsorption and desorption loops were analyzed. The pore size distribution and pore type characteristics of different macerals were obtained by isothermal adsorption line and desorption loop analysis. The results show that: the coal and chitin group accords with the II type adsorption isotherm, the vitrinite and the inertinite are in accord with the III type isotherm; the chitin has larger small pores content and pore volume and specific surface area than that of the vitrinite and the inertinite. In the chitin group, the open pores have a larger percent in the pores in which the diameters are greater than 5.4 nm, and the vitrinite group and inertinite group contain only a very small percent of open air holes. The specific surface area and pore volume fractal dimension of chitin group were the smallest, and the vitrinite group was the largest.