The nanostructured CePO₄ with monoclinic phase was controllably synthesized through a low temperature hydrothermal route by varying the reactant PO3-4/Ce3+ molar ratio. The structures, morphologies, sizes and luminescence properties of the products were studied by XRD, FE-SEM, DSC-TG and photoluminescence spectra. With the PO3-4/Ce3+ molar ratios increased, the synthesis temperature of as-synthesized monoclinic CePO4 was decreased, and the morphologies underwent the evolution from the rod-like nano-structures to the flower-like nanoclusters. When the PO3-4/Ce3+ molar ratio was lower, CePO4 nanorods were obtained, while the PO3-4/Ce3+ molar ratio was higher, the monoclinic CePO4 flower-like nanoclusters were crystallized. The photoluminescence spectrum showed that the CePO4 nanorods exhibit better photoluminescent property than the CePO4 flower-like nanoclusters. With the cycling use of phosphoric acid, the low-cost preparation of CePO4 could be achieved.