Methane, the major constituent of natural gas, was converted to higher hydrocarbons by a microwave plasma. The yield of C2+ products increased from 29.2% to 42.2% with increasing plasma power and decreasing flow rate of methane. When catalysts were used in the plasma reactor, the selectivities of ethylene and acetylene increased, while the yield of C2+ remained constant. Among various catalysts used, Fe catalyst showed the highest ethylene selectivity of 30%. And when the actual natural gas was introduced, more C2+ products were obtained (46%). This is due to the ethane and propane in the natural gas. Applying electric field inductance for evolving the high plasma, we obtained high C2+ products of 63.7% when Pd-Ni bimetal catalyst was used.