Carbon nanofiber-supported MnOx composites were prepared by electrodepositing MnOx nanoparticles directly onto electrospun carbon nanofibers. The morphology and size of MnOx nanoparticles were controlled by the surface treatment of carbon nanofibers and the electrodeposition duration time. SEM, TEM/EDS, elemental analysis, and XRD were used to study the morphology and composition of MnOx on the nanofibers. The resultant MnOx/carbon nanofiber composites were used directly as the anode material in lithium half cells and their electrochemical performance was characterized. Results show that MnOx/carbon nanofiber composites prepared by different deposition durations have high reversible capacity, good capacity retention, and excellent structural integrity during cycling.