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The effects of non-thermal plasma on selective catalytic reduction of NO x by CH 4 (CH 4 -SCR) over an In/H-BEA catalyst were investigated over a wide range of reaction temperatures (523−823 K). The significant promotion effect between non-thermal plasma and CH 4 -SCR was exhibited at low temperatures from 523 to 698 K, while this synergetic effect gradually reduced with the increase of the reaction temperature. The NO x removal efficiency of the non-thermal plasma-facilitated CH 4 -SCR (PF-CH 4 -SCR) hybrid system increased at low temperatures because of the promotion of NO oxidation and CO yield by non-thermal plasma. Optimization of CH 4 injections was an alternative solution for improving activity of In/H-BEA for the PF-CH 4 -SCR hybrid system. When 400 and 200 ppm of CH 4 were injected into plasma and the SCR reactor, respectively, the PF-CH 4 -SCR hybrid system showed a wide operation window temperature. Catalyst characterizations showed that addition of nonthermal plasma could promote SO 2 and H 2 O tolerance of In/H-BEA, because of the inhibition of SO 2 oxidation, InO + sulfating, and indium oxide agglomeration.