In this work DBD (dielectric barrier discharge) plasma treatments of 10%Ni/Al2O3 and 1%Pt/Al2O3 catalysts have been conducted to study the principles of plasma treatment of supported catalysts. It was found that 10%Ni/Al2O3 and 1%Pt/Al2O3 catalysts treated by plasma exhibit a higher catalytic activity and a better stability than the catalysts prepared without plasma treatment. Methane conversion over the plasma treated catalyst is 3-5% higher than on untreated catalysts. The metal species dispersion also increased after plasma treatment, which leads to improvement of the interaction between active species and supports, the catalytic activities and the resistance to carbon deposition.