Abstract: The methane reduction behavior was studied in a molten alkali carbonates (Li2CO3、Na2CO3、K2CO3) system. Thermodynamic and experimental investigations were performed to quantify the product compositions. The results showed that the CO and CO2 contents in the product gases increased with the reaction temperature, whereas it decreased with the reaction time. The reaction activity order of carbonates was Li2CO3 > Na2CO3 > K2CO3. The selectivity of CO in the mixed molten salts system was higher than that in a pure system. The mixed molten salts system was more suitable than pure system as the reaction medium of CH4 conversion. H2 was mainly from the CH4 cracking, and CO and CO2 was from the reaction between CH4 cracking carbon and molten alkali carbonates.