Nanorods and nanoparticles of CeO2 were successfully synthesized and used as support of Pd/CeO2 catalysts. It is found that the nanorods show obvious advantages as the support, compared with the nanoparticles. Low efficiency in the formation of reduced Pd, and partial encapsulation of Pd species account for the poor activity of Pd supported on CeO2 nanoparticles. On the contrary, a favorable interaction between Pd and the crystal planes [1 1 0] and [1 0 0] of CeO2 nanorods effectively promotes the reducibility of Pd species, resulting in much better catalytic performance of Pd/CeO2 catalyst for CO oxidation.