Cerium hydrate fiber (CHF), which showed an aspect ratio greater than 100, was synthesized by a novel method, which used the mixing of cerium nitrate (Ce(NO3)3), sodium hydrate (NaOH) and citric acid (C6H8O7) synthesized at a relative low temperature and ambient pressure. The precipitates were characterized by XRD, SEM and TEM. The results showed that in addition to fibers, two morphologies could be obtained depending on the synthesizing conditions. Aging time and formulation were two key factors for the control of the aspect ratio of the precipitates. By a heating treatment at 600oC for 2 h, the homogenous and well-crystallized cerium dioxide (CeO2) fiber can be fabricated. The effects of synthesis parameters, such as the concentration of the starting solution, aging period, and pH value were reported and discussed.