Biomorphic pure ZnO and porous CeO2–ZnO hollow fibers have been fabricated using cotton as biotemplates. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Brunauer–Emmett–Teller (BET). XRD results indicate that the CeO2–ZnO sample is well crystallized and shows a mixed phase of CeO2 and ZnO. Compared with pure ZnO, the CeO2–ZnO sensor exhibits much better response to ethanol with high sensitivity and good selectivity at 260°C, which is mainly contributed to the increasing of active surface area and gas diffusion.