This study investigated the catalytic pyrolysis of kraft lignin using an in-situ generated Fe-based catalyst derived from iron ore. The fresh and spent catalysts were characterized by a transmission electron microscope to explore the morphological changes of the catalysts. The performance of the catalysts was evaluated by a segmented pyrolysis reactor combined with time-of-fight mass spectrometry. The results showed that the fresh catalysts had a particle-like morphology, while the spent catalysts seemed to be sintered. Compared to unreduced iron ore and commercial Fe2O3, reduced iron ore significantly promoted the production of monocyclic aromatic hydrocarbons. A relative content of 81% was achieved for monocyelic aromatic hydrocarbons at the optimized reaction temperature of 550 ℃, with benzene, toluene, xylene and trimethylbenzene accounting for 46% , 34%, 13% and 7% , respectively. Moreover, the possible pathway for kraft lignin via catalytic pyrolysis was proposed based on dehydroxylation and demethoxylation. This work suggests that a low-cost iron ore catalyst could be potentially applied to pyrolyze kraft lignin to produce valuable bio-based aromatic hydrocarbons.