The outstanding electric, mechanical and thermal properties of carbon nanotubes (CNTs) have stimulated widespread interest for fundamental research and applications. This work demonstrates the growth of vertically arranged CNTs on Si substrate by microwave plasma enhanced chemical vapor deposition (MPECVD) with optimized operation parameters. Iron oxide (Fe3O4) nanoparticles (NPs) were synthesized by co-precipitation method. The catalytic Fe3O4 NPs were distributed on Si by spin coating. CNTs were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. Through the study, the authors have successfully grown CNTs based on iron oxide nanoparticles by MPECVD at the grown temperature of 650°C.