Abstract: To study the pore structure damage characteristics in pulverized coal and its influence on coal and gas outburst, the methods of field sampling and laboratory testing were used to determine the parameters systematically, such as industrial analysis, true density, low temperature (77 K) N₂ adsorption, high pressure gas adsorption and gas diffusion initial velocity for the six different particle sized samples from the No. 12 coal seam of Dalong Coal Mine in Tiefa Mining Area. The results indicated that the basic composition of pulverized coal had no great changes, but the pore structure, the gas adsorption/diffusion properties changed significantly; with the increase of the pulverization degree, the specific surface area, the pore volume of coal samples increased in a power function tendency; the smaller sized coal particles had higher gas adsorption capacity and faster initial gas diffusion rate under the same conditions, which could promote the launch and development of coal and gas outburst.