Abstract: In order to explore the influence of buried depth and particle size on the minimum ignition temperature of coal dust layer, coal samples from Jibei mining area were selected. Based on the study of physicochemical properties of deep coal seams, the minimum ignition temperature of coal with different depths and particle sizes was measured by hot plate experiments. The results show that in the experimental temperature range, the thickness of the coal dust layer is 5mm, the buried depth increases, the volatile content increases from 33.65% to 38.9%, and the minimum ignition temperature of the coal dust layer decreases from 330°C to 270°C. The phenomenon of layer fire can be observed with the naked eye. As the particle size of the coal sample decreases continuously, the minimum ignition temperature of the coal dust layer of different buried coal samples is significantly reduced. When the coal dust layer is 5 mm, ith the coal sample particle size decreasing from 180μm to 75μm, the minimum ignition temperature of the coal dust layer of three different buried depths decreased by 16%, 19% and 25%, respectively, and the difference was significant.