Abstract: According to the requirements of filling gangue in a mine, artificial classification for broken gangue is done. Through compression tests of different sizes distribution of coal gangue, compression laws of gangue is obtained, and the suitable size distribution plan of filling gangue is determined. Experimental resuls show that small particle size coal accounts for 50%, middle size content for 30% and large particle size for 20% of the content are the best collocation plan. On the basis of the plan, the content of small particle size can properly increase and reduce the content of large particle size of coal gangue according to actual filling.