Abstract: To reveal the influencing mechanism of adsorption pore structure on gas emission characteristics of coal, with the typical coal samples from Fukang coal mining area of Xinjiang, low temperature nitrogen adsorption experiment and initial velocity of diffusion of coal gas experiment are carried out. The characteristic parameters of adsorption pore and its influence on initial velocity of diffusion of coal gas are studied. The experimental results have shown that：1) The main transition forms of gas diffusion in adsorption pore are the Knudsen and transition; 2) The parameters of adsorption pore have different influences on gas diffusion characteristics: the greater the average pore diameter is, the smaller the gas diffusion resistance is and the greater the initial velocity of diffusion of coal gas is; the greater the specific surface area, volume of pore and each pore size are, the smaller the initial velocity of diffusion of coal gas is; 3) The initial velocity of diffusion of coal gas has negative liner correlation with proportion of micropore and transition pore volume, positive liner relationship with the proportion of mesopore volume, and no obvious relationship with the proportion of specific surface area of each pore size; 4) In the study range, the fractal characteristics of coal pore are significant, the initial velocity of diffusion of coal gas decreases with the linear increase of fractal dimension.

Key words: pore structure, initial velocity of diffusion of coal gas, fractal dimension, adsorption pore