Hierarchical mesoporous alumina fiber was synthesized by using collagen fiber as the template, and characterized by means of scanning electron microscopy, transmission electron microscopy, N-2 adsorption techniques, X-ray photoelectron spectroscopy, and X-ray diffraction. The alumina fiber obtained is approximately 1-4 mu m in outer diameter and 0.5-1 mm in length. The pore size distribution of the alumina fiber is narrow (2-20 nm), and its pore size is controllable by varying preparation methods. This study indicates that collagen fiber, which has hierarchical supermolecular structure, could be used as an ideal template to prepare well-defined porous metal oxide fibers.