Lignin is a crucial raw material for the synthesis of phenol due to its high oxygen concentration; however, the selectivity of phenol in pyrolysis products is low. This study chose cerium oxide as the coupling agent for molten salts, and the reaction’s process conditions—including temperature and catalyst dosage—were examined. The influence of metal loading on the reaction and byproducts of catalytic pyrolysis was examined. The outcomes demonstrated that the best monophenol production was accomplished at 550 °C and an Fe loading of 15 wt.%, with 93.93 wt.% monophenols in the bio-oil. While methoxy was more easily broken and rearranged, producing more monophenols, the presence of the catalyst enhanced the oxidation of Cα-OH and the breaking of β-O-4 bonds, which is significant for the study of lignin pyrolysis.