In phosphoric acid system, by altering the reactant PO_4~(3-)/Ce~(3+) molar ratio, CePO_4 nanorods/wires were synthesized through hydrothermal route, and the structure and morphology evolution from CePO_4 to CeO_2 were also detected. The structures, morphologies, sizes and luminescence properties of the products were studied by XRD, SEM, EDX and luminescence spectra. The results indicate that with decreasing of the PO_4~(3-)/Ce~(3+) molar ratio, CePO_4 nanorods changed to nanowires, which further resulted in the formation of one dimesional CeO_2 nanowires at lower PO_4~(3-)/Ce~(3+) molar ratio. The photoluminescence spectrum shows that CePO_4 nanorods/wires have a rather broad emission between about 300～400 nm, which is caused by the 5d-4f emission of Ce~(3+). And the CePO_4 nanowires exhibit better photoluminescent property than the CePO_4 nanorods.