In a dielectric barrier reactor (DBD), plasma-assisted direct conversion of CH4 and CO2 to liquid products (methanol, ethanol, etc.) under atmospheric conditions was performed. Due to its excellent ability to activate CO2 and promote chain growth, Fe is an ideal candidate for catalyst design. Meanwhile, graphite carbon nitride (g-C3N4) with Lewis and Brönsted basic sites further enhances its catalytic performance. Therefore, combining Fe and g-C3N4 holds great potential for catalyst synthesis and applications. In this paper, we prepared a highly active catalyst (Fe/g-C3N4) using a non-noble metal by impregnating Fe onto the g-C3N4 support. When 10% Fe/g-C3N4 was half-filled in the discharge region, the conversions of CH4 and CO2 were 22% and 18%, respectively, and the liquid product selectivity was 40.1%. In the liquid products, the selectivity of alcohol liquid products can reach 35%, of which methanol can reach 24.4%, higher than the reported 11.9%.