Different particle sizes of coal relics in coal mining workings have different contact areas with air, different numbers of surface active structures for coal oxygen reactions, and different rates of oxygen consumption. In this paper, the programmed warming experiment system was used to conduct programmed warming experiments on bituminous coal samples, analyze the law of O2, CO, C2H4 and C2H6 gas production in the warming and oxidation process of different particle size coal samples, and calculate the size of oxygen consumption rate at each temperature point of different particle size coal samples, and determine the propensity of coal to spontaneous combustion by analyzing the cross point temperature of different particle size coal samples. The relationship between particle size and oxidation of bituminous coal samples was analyzed, and the influence function between particle size and oxygen consumption rate was deduced. The experiments showed that the oxygen consumption rate of different particle sizes increased with the increase of temperature, and the smaller the particle size, the faster the oxygen consumption rate, the higher the concentration of released gas, and the stronger the oxidative spontaneous combustion. When the oxidation temperature was consistent, the O2 consumption rate and the concentration of released gas increase with the smaller particle size, and the oxygen consumption rate and the particle size of coal samples met the negative exponential relationship.