Fe3O4/carbon composite nanofibers were prepared by electrospinning polyacrylonitrile (PAN), iron (III) acetylacetonate (AAI) and dimethyl formamide (DMF) compound solutions, followed by stabilization and carbonization processes. Emphasis was put on the influence of AAI on reactions during stabilization and carbonization. The effect of Fe3O4 on catalytic graphitization and electrical conductivity was also studied. Experimental results show that AAI has participated in the reactions and structural changes of PAN during stabilization and carbonization, and is evidenced to promote the processes. Fe3O4 nanoparticles exhibit catalytic effect on carbonization process that promote graphitization by a catalytic effect at low AAI content and inhibit the formation of graphitized layers when AAI content is excessive. Therefore, there exists an optimum AAI content (C-o) where composite nanofibers show the maximum graphitization degree and electrical conductivity. With proper amount of AAI addition, Fe3O4/carbon composite nanofibers showing high graphite degree and electrical conductivity could be achieved. (C) 2012 Elsevier Ltd. All rights reserved.