Abstract: Biomorphic CeO2 fibers with the biomorphic structure of filter paper and uniform nano-pores were successfully synthesized by taking the filter paper as template. Many methods were used to characterize the CeO2, including thermogravimetric analysis, X-ray diffraction, electron microscopy, nitrogen adsorption-desorption,etc. The effect of the precursor solution concentration on the structure of CeO2 fibers, and the catalytic property of CeO2 were studied. The results indicate that the synthesied CeO2 fibers consisting of 5-10 nm CeO2 nanocrystals with the largest surface areas of about 84.7 cm2·g-1 were 0.5-5 mm in length, 5-20 μm in diameter and 3 nm in pore size, when the concentration of the precursor solution was 0.02 mol·L-1. These porous CeO2 fibers possessed a superior catalytic activity for CO oxidation and 100% CO conversion at 450 ℃. With the increase of precursor solution concentration, the copy effect of product for the template was impacted due to the grain accumulation.