The phase-change action causes three phenomena: an increase in the width of the original crack structure of coal, mutual extension and penetration, and generation of new fractures. Fracture evolution process causes coal and cement to be dislodged, forming micropowders, the range of coal particle size is negatively correlated with temperature and pressure of SC-CO 2 . The SC-CO 2 phase change inside coal pores increases pore size and accumulated pore volume. The effect of SC-CO 2 phase-change fracturing is enhanced with increasing temperature and pressure. Article Highlights• Supercritical carbon dioxide phase change acts on the coal and causes it to be destroyed at the microcrack scale. • Supercritical carbon dioxide phase change causes coal fissures to widen, penetrate, extend, and create new cracks. • The phase-change fracturing of a supercritical carbon dioxide jet breaking coal is the cause of coal powders. Keywords Supercritical carbon dioxide jet • Coal powder • The SC-CO 2 phase change fracturing • Original crack • Pore