Factors influencing methane conversion in a high-frequency pulsed plasma were studied. Pulse frequency is the most important factor influencing acetylene selectivity and methane conversion rate that represents electric energy efficiency. The high pulse-frequency plasma promotes acetylene formation and improves methane conversion rate. With increasing pulse voltage, acetylene selectivity increases, but methane conversion rate decreases. The temperature of the background methane gas does not markedly influence methane conversion in a temperature range of 20 to 200 degreesC. A co-axial cylindrical reactor with a fine central anode is favorable to practical use of methane conversion.