Abstract: To study the efficient combustion of block coal, the paper constructed a central electrode structure combustion aid device using alumina ceramic as the medium. In accordance with the unique discharge environment during the combustion of irregular block coal, the study investigated the system matching of excitation source parameters and device structure under a special gas atmosphere, as well as the discharge characteristics and their effects on combustion in the plasma-assisted coal bed with medium barrier discharge. The results show that stable discharge can be achieved within the range of 12~16 kV of externally applied peak voltage, and the discharge power is positively correlated with the applied voltage. With an inner diameter of 30~60 mm and a constant voltage, the discharge power initially increased and then decreased as the inner diameter increases. With the introduction of medium barrier discharge plasma, the combustion front of the coal bed gradually expands, and the combustion limit is extended. The combustion temperature and mass attenuation are significantly improved, and are positively correlated with the voltage. The early-stage temperature and mass during the combustion aid process sigmifcantly change with voltage variations.