Abstract: Coal undergoes crushing and pulverization under the action of mechanical cutting and geostress during the mining. Crushing and pulverization can reduce particle size and increase specific surface area, and lead to the occurrence of phenomena such as the crystal structure destruction, new surfaces generation, the covalent bonds break, and the free radicals production. Based on mechanochemical theory and starting from the perspective of modification through crushing and pulverization, methods including microscopic characterization, theoretical modeling of coal molecules, molecular dynamics simulations, and thermal analysis are employed to investigate the evolution of the microstructure and the oxidative kinetics of coal beneath the macroscopic phenomenon of crushing. On this basis, mechanisms by which mechanochemical effects influence coal spontaneous combustion are elucidated. The results show that: Mechanical crushing and pulverization can disrupt the continuity of the coal microcrystalline structure, inducing higher defect concentration and lattice distortion at the surface fractures of coal compared to the original coal, resulting in atoms at these locations being in a high-energy, unsaturated bonding state;The process of crushing and pulverization can induce the disordering of the microcrystalline structure of coal, the reorganization of functional groups, the exposure of active sites, and the reduction of chemical bond stability; Mechanical crushing and pulverization can disrupt the long aliphatic chains and the original hydrogen bond network in coal, generating unstable free radicals. These free radicals can further trigger a chain reaction leading to spontaneous combustion of coal by capturing hydrogen atoms. The input of mechanical energy alters the molecular configuration of coal, leading to local stress concentration, and some chemical bonds are in a transitional state before critical fracture; Thermal analysis experiments on crushed and pulverized coal samples have confirmed that as the degree of crushing and pulverization increases, the characteristic temperature points for coal spontaneous combustion decrease. The oxidation exothermic curve becomes “narrow and sharp”, the apparent activation energy decreases, and the oxidation process accelerates. From the above results, the mechanical crushing and pulverization process disrupts the microcrystalline structure of coal, induce lattice distortion, and increases the internal energy of the system. It destroys the long aliphatic chains and hydrogen bond networks, leading to the reorganization of functional groups and the generation of unstable free radicals. Furthermore, it changes the molecular configuration, weakens the bond order of some chemical bonds, and causes molecules to accumulate defects, resulting in a metastable state. Overall, the mechanochemical effects mentioned promotes the enhancement of its chemical activity, resulting in a decrease in the apparent activation energy of each sub-reaction stage of coal spontaneous combustion, which exerts a “mechanical activation” effect on the coal body, exacerbating the risk of spontaneous combustion. This provides a theoretical basis and a new perspective for explaining why areas with severely fragmented coal bodies—such as those near on-site stop lines, open-cut eyes, fault structural zones, and fractured coal pillars—are prone to spontaneous combustion.