Abstract: Using a coal flash point tester, specific surface area and aperture tester, and an infrared spectrometer, the changes in the ignition point, specific surface area, and functional groups of coal samples pre-oxidized at different temperature were studied to reveal the ignition point and specific surface area, pore size and functional group change characteristics of weakly caking coal during oxidation. The results of the study show that as the pre-oxidation temperature gradually increases, the ignition point fluctuates but overall it decreases. After the initial oxidation, the specific surface area of the coal sample increased approximately 4 times. After the secondary oxidation, the specific surface area of the coal sample increased by approximately 32 times than that of the fresh coal sample. The large coal samples mainly consist of macropores, and the proportions of mesopores and micropores are very small. After the initial oxidation, the proportion of macropores decreases sharply, the proportion of mesopores sharply rises and dominates; after the secondary oxidation, the void volume of coal samples decreased, in which the volume of the mesopore sharply decreases, the proportion of the micropore volume increased rapidly and dominated. As the pre-oxidation temperature increases, the number of oxygen-containing functional groups increases, the number of saturated hydrocarbon functional groups decreases, and the number of aromatic ring functional groups does not change substantially.