Kinetic modeling of non-thermal plasma chemistry is conducted to investigate hydrocarbon (CH(4), C(2)H(4), C(3)H(6), and C(3)H(8)) effects on the promotion of NO-NO(2) conversion. A reduced plasma chemistry model, in which radical reactions are selectively involved, is validated with experimental data. The higher reactivity of hydrocarbon additive with O radicals, which produces initial radicals, is requisite to initiate hydrocarbon decomposition, thus providing NO-NO(2) conversion. Initial radicals by plasma discharge induce continual hydrocarbon decomposition and this self-preserved reaction mechanism greatly contributes to the promotion of energy efficient NO-NO(2) conversion. Increase in the conversion extent by ethylene and propylene additives is substantial because of their stronger affinity with O radical. The primary routes of NO-NO(2) conversion process differed by hydrocarbon additives are presented and discussed with the assistance of sensitivity analysis.