To explore the main influencing factors of atomic ratio (O/C, N/C, and H/C) as well as microcrystalline structure (d(002), L-a, L-c, and M-c) on thermal properties (specific heat capacity, thermal conductivity, and thermal diffusivity) at certain temperatures within 30.0-300.0 degrees C, three coal samples were collected from coal mines of Dafosi, Yangjiaping, and Hujiahe in Binchang coalfield, Shaanxi Province, PR China. Thermal properties of coal samples were determined by laser-flash apparatus in nitrogen atmosphere. After temperature treated at 30.0, 60.0, 90.0,..., 300.0 degrees C in nitrogen atmosphere, the atomic ratio and microcrystalline structure of samples were measured by proximate analyser and X-ray diffractometer. The results indicated that with an increment in the temperature, the value of H/C for three coal samples diminished slightly and then promptly, whereas O/C diminished slightly and then increased before 120.0 degrees C, as well as finally increasing, and the N/C had no obvious change. Concurrently, the microcrystalline structure of coal samples became more orderly and complete. Furthermore, the TD decreased with temperature, the SHC and TC showed an opposite trend with TD. Based upon grey correlation analysis, the major influencing factors of atomic ratio and microcrystalline structure on thermal property were approached. The results provided insight into the physicochemical properties of the coal of interest for predicting the progress of coal spontaneous combustion. (C) 2021 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.