A flower-like Fe3O4/carbon nanocomposite with nano/micro hierarchical structure is prepared by controlled thermal decomposition of the iron alkoxide precursor, which is obtained via an ethylene glycol-mediated solvothermal reaction of FeCl3 and hexamethylenetetramine (HMT) in the absence of any surfactant. The nanocomposite is characterized by the assembly of porous nanoflakes consisting of Fe3O4 nanoparticles and amorphous carbon that is in situ generated from the organic components of alkoxide precursor. When used as the anode materials for the lithium-ion batteries, the resultant nanocomposite shows high capacity and good cycle stability (1030mAhg−1 at a current density of 0.2C up to 150 cycles), as well as enhanced rate capability. The excellent electrochemical performance can be attributed to the high structural stability and high rate of ionic/electronic conduction arising from the synergetic effect of the unique nano/micro hierarchical structure and conductive carbon coating.