Display omitted •The thermal properties of coal at cryogenic conditions (−100 to 0 °C) is investigated.•The thermal diffusivity of coal increases by 121.4 % with decreasing temperature.•The specific heat capacity of coal decreases by 57.9–65.9 % with decreasing temperature.•The volatile matter and carbon content in coal have the highest correlation with thermal properties (∼0.9).•The thermal diffusivity of coal increases with increasing volatile matter content but decreases with increasing carbon content. The thermal properties of coal are important factors that influence the heat and mass transfer during the pyrolysis process. Therefore, thermal properties were investigated for two tar-rich coal under cryogenic temperature and pyrolysis condition using laser flash analyzer. Gray correlation analysis and chemical composition analysis are combined to analyze the impact of chemical properties on thermal properties. With decreasing temperature, the thermal diffusivity of coal experiences a significant increase by 108.9–121.4 %, while the specific heat capacity decreases by 57.9–65.9 %. The volatile matter and fixed carbon content in tar-rich coal have the highest correlation with thermal properties (∼0.9), followed by moisture content (∼0.62), while the ash content has the lowest correlation with thermal properties (∼0.5). The thermal diffusivity of tar-rich coal increases with increasing volatile matter content. Furthermore, within the range of −100 °C to 300 °C, the thermal diffusivity of tar-rich coal decreases with increasing carbon content, while the specific heat capacity increases with increasing carbon content. The results indicate that under low-temperature cryogenic conditions, the internal heat transfer capability of tar-rich coal is significantly improved.