Abstract: The molten salt electrolysis graphitization process provides an efficient and green pathway for the electrochemical conversion of biomass resources into high value-added graphitized carbon. However, it suffers from poor reaction kinetics and difficult structural modulation. In this study, we report the process and mechanism of graphitization and tubulation of Fe-assisted in molten salt CaCl2 at low temperature. The results showed that the graphitization rate could be significantly enhanced, the reaction time shortened and the energy consumption reduced with the assistance of Fe. Meanwhile, Fe also induced the evolution of the product's morphology from sheet structure to tube-sheet hybrid structure. Experimental and simulated multiscale analyses revealed the kinetics of the Fe-promoted deoxygenation reaction and the deoxygenation pathway, and the mechanism of Fe-regulated directed growth of carbon rings to build tube-sheet composite structures. Graphitized carbon exhibited a specific capacity of 336.37 mAh g-1 (1 C) when served as a negative electrode for lithium-ion batteries. The electrochemically coupled Fe-catalyzed synergistic strategy provides a rational pathway for the high-value utilization of low-quality carbon-containing solid wastes (e.g., woody biochar).