Nonthermal RF plasma modification has been applied to alumina-supported Pd catalysts for selective hydrogenation of acetylene in the presence of ethylene. High ethylene selectivity and good acetylene conversion activity were obtained at low temperatures on the H-2 plasma-treated catalyst without the in situ reduction procedure. The results suggest some Pd nitrate was reduced to Pd metals during H-2 plasma treatments at room temperature. XRD, FT-IR, and TPR results confirm the reduction effect of plasma treatments. The results also suggest that the H-2 plasma treatment produces more active sites on the surfaces of alumina-supported Pd catalyst for selective hydrogenation of acetylene to ethylene and limits the production of ethane and green oil than the catalysts prepared using the conventional procedures. It demonstrates that the RF nonthermal plasma treatment is an effective way to manipulate surface properties and the interaction between metals and supports for the design of novel catalysts for selective hydrogenation of acetylene.