The purpose of this paper is to investigate the characteristics and optimum operating conditions of the plasmatron-assisted CH 4 reforming reaction for the hydrogen-rich gas production. In order to increase the hydrogen production and the methane conversion rate, parametric screening study was conducted at various CH 4 flow ratio and steam flow ratio and with and without adding catalyst in the reactor. High-temperature plasma flame was made with air and arc discharge, and the air flow rate and the input power were set to 5.1 L/min and 6.4kW, respectively.When the steam flow ratio was 30.2%, the hydrogen production was maximized and the optimal methane conversion rate was 99.7%. Under these optimal conditions, the following syngas concentrations were determined: H 2 , 50.4%; CO, 5.7%; CO 2 , 13.8%; and C 2 H 2 , 1.1%. H 2 /CO ratio was 9.7 and the hydrogen yield was 93.7%.