An advanced flue gas conditioning technology was developed through in situ oxidation of SO 2 using dielectric barrier discharge and heterogeneous condensation of SO 3 on fly ash (FA). Orthogonal experiments were carried out for the design of discharge structure, whereas the optimal condition was achieved at 8 kV of discharge voltage, 2 mm of discharge gap and 56 cm 2 of discharge area; single factor experiment was introduced here to investigate impacts of various elements (gas flux, temperature, concentration of SO 2 and relative humidity) on oxidation of SO 2 , results showed that the oxidation of SO 2 was in inverse proportion to gas flux and SO 2 concentration, whereas in direct proportion to relative humidity, the optimal temperature was detected at 45 C. Physical and chemical characterizations of treated samples were performed in this work using scanning electron microscopy (SEM) and Fourier transform infrared (FTIR). Particle coagulation was found in the SEM, and a continuous peak rise of sulfate at 1086 cm À1 was detected by the FTIR analysis, which indicated that SO 3 generated by in situ oxidation of SO 2 could be successfully absorbed by the surface of FA particles. The specific resistance of conditioning FA showed a remarkable decrease from 1.41 Â 10 13 to 5.74 Â 10 11 Ω cm compared with the untreated sample.