Using monoclinic CePO4 as cores, uniform CePO4@LaPO4 single-crystalline one-dimensional nanostructures have been successfully synthesized via a facile and simple hydrothermal method. The CePO4@LaPO4 one-dimensional nanostructures have highly enhanced photoluminescent emission compared to the pure-phase CePO4. The uniform LaPO4 sheaths effectively eliminated surface trap-states and remarkably increase the luminescent efficiency. The products were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectra (EDS), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL).