Fe2O3-filled carbon nanotube material was prepared by filling carbon nanotubes (CNTs) with iron nitrate and then heating in an argon flow. The morphology and structure of this material were investigated by transmission electron microscopy (TEM), scanning electron microscopy (SEM) coupled with X-ray energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) measurements. The morphology, particle size and amount of iron oxide that filled CNTs depended on the amount of iron nitrate precursor. When Fe:C=1:17wt%, almost all of the iron oxide particles resided inside CNTs and their particle size was smaller than that at Fe:C=1:8wt%. The electrochemical properties of this material were investigated using cyclic voltammetry (CV) and galvanostatic cycling.