Abstract The conversion of CH4 and CO2 to syngas in a dielectric barrier discharge reactor was performed. The conversion to syngas increased with input power and decreased with total flow rate, whereas the selectivity of H2 and CO did not change significantly. When CH4/CO2 ratio increased, the conversion of CH4 and the selectivity of H2 and CO decreased. The highest conversion of CH4 and CO2 was 77.72% and 67.88%, respectively. It was confirmed that the DBD system can be used for producing syngas with the controllability in H2/CO ratio.