<p>Currently, tar-rich coal (TRC), which contains abundant oil and gas resources, is mainly used for direct combustion power generation. However, this practice not only wastes the valuable oil and gas resources in TRC but also leads to substantial carbon emissions and severe environmental pollution. Drawing inspiration from the concept of in situ fluidised mining of coal, a previous study proposed an intelligent unmanned mining machine (IUMM) equipped with a microwave irradiation device and an in situ intelligent mining method for efficiently utilising TRC and achieving near-zero CO₂ emissions. One of the important functions of the IUMM is the use of microwave pyrolysis to fracture TRC. The first step is to address the theoretical and methodological aspects of microwave irradiation pyrolysis and fracturing of TRC and understand the variations in its physical and mechanical properties. To describe the stress–strain response of TRC under microwave irradiation and analyse the changes in its strength, brittleness and deformation, a study on the strength characteristics and damage properties of TRC induced by microwave was conducted. The strength degradation law of TRC resulting from different irradiation was shown, and the microwave irradiation factors influencing the strength degradation were elucidated. Based on Weibull statistical strength and the damage mechanics theory, a thermal damage constitutive model for microwave-irradiated TRC was derived. The accuracy of the thermal damage constitutive model was validated by comparing it with the experimental results. This study provides a theoretical basis for determining rational IUMM mining schemes and lays the foundation for exploring in situ mining and transformational utilisation methods for TRC, as well as achieving environmentally friendly, clean and low-carbon development and utilisation of TRC.</p>