Ce3+ and Tb3+ coactivated LaPO4 nanowires and micrometer rods were synthesized by hydrothermal methods. Their fluorescent spectra and dynamics were systematically studied and compared. The results indicated that the extinction coefficients of Ce3+ and Tb3+ in nanowires were higher than those in micrometer rods. The electronic transition rates of Ce3+ and Tb3+ in nanowires had little variation in contrast to those in micrometer rods, and the energy transfer rate and efficiency of Ce3+ --> Tb3+ in nanowires were reduced greatly. It is important to observe that the brightness for the 5D4-7F5 green emissions of Tb3+ via energy transfer of Ce3+ --> Tb3+ in nanowires increased several times that in micrometer rods. This was attributed to the decreased energy loss in the excited states, being higher than 5D4 due to the hindrance of the boundary.