Abstract: To investigate the effects of CO₂-water on the pore-fracture structure and mechanical properties of coal, this study employed a self-developed high-temperature and high-pressure acidification experimental system. SJG bituminous coal and DF anthracite coal were selected as test samples, and their pore-fracture structural changes and mechanical responses before and after treatment at 40 ℃ under 2 MPa CO₂ pressure were examined using CT scanning, SEM-EDS, and ultrasonic testing. The results showed that the acidification treatment significantly altered the pore-throat structure of the coal samples. For SJG bituminous coal, the pore-fracture proportion increased by 4.33%, while the mineral content decreased by 0.38%. After dissolution, the pore-fracture structure extended along the bedding planes, and the proportion of pore throats with equivalent diameters exceeding 1 000 μm increased, exhibiting the characteristics of an interconnected fracture network. In contrast, DF anthracite exhibited a weak acidification response, owing to its high degree of metamorphism, dense structure, and enrichment of silicate minerals. Its pore-fracture proportion increased by only 0.08% and mineral content decreased by 0.05%, while the proportion of pore throats with equivalent diameters exceeding 200 μm showed only a slight increase, indicating restricted fracture development. Mechanical testing revealed that under CO₂ pressurization, both coal samples exhibited decreased wave velocity, deteriorated elastic modulus, and increased Poisson's ratio, with more significant damage observed in SJG bituminous coal. DF anthracite, however, showed a sudden drop in wave velocity, attributable to dissolution inhibition and stress concentration. The study revealed that metamorphic grade and mineral composition regulate the sensitivity of coal to CO₂ acidification. Medium- to low-rank bituminous coal (SJG) contains more pre-existing pore-fracture structures, which makes it easier for stress to break through fracture tips and form an interconnected fracture network. In contrast, the acidification effect in high-rank anthracite (DF) is inhibited by inert minerals, resulting in only localized fracture development. These findings provide important insights for CO₂-enhanced coalbed methane recovery in both bituminous and anthracite seams.