Abstract: PM and THC of mining diesel are key precursors of secondary aerosols and ozone, yet conventional DPF/DOC systems suffer from low-temperature inactivity, high energy demand and poor load flexibility. This paper couples a coaxial DBD plasma reactor with a Mn-oxide/carbon composite catalyst to investigate the simultaneous removal of PM and THC. PM conversion rises with applied voltage（13-17 kV） but dropped markedly when flow rate（2-5 L/min） or inlet concentration（33.75-99.4 mg/L） increases. Orthogonal tests yield the optimum at 17 kV, 3L/min and 50.1 mg/L, giving 52.7% PM removal. With 400 g catalyst, THC removal reaches 59.2% at 17 kV, 3 L/min and 120 mg/L; the catalyst alleviates efficiency loss under high flow and concentration, evidencing a plasma-activation/catalytic-oxidation synergy.