LaPO(4):Ce(3+), Tb(3+) nanoparticles were prepared by the reverse microemulsion with functional monomer, methyl methacrylate (MMA) as oil phase, and LaPO(4):Ce(3+), Tb(3+)/poly(methyl methacrylate) (PMMA) nanocomposite was obtained via polymerization of MMA monomer. The nanoparticles and nanocomposite have been well characterized by XRD, SEM, TEM, UV/vis spectrum, photoluminescence excitation and emission spectra and luminescence decays. The obtained solid nanocomposite LaPO(4):Ce(3+), Tb(3+)/PMMA is highly transparent and exhibits strong green photoluminescence upon UV excitation, due to the integration of luminescent LaPO(4):Ce(3+), Tb(3+) nanoparticles. The luminescent lifetime of Tb(3+) is determined to be 1.25 ms in the nanocomposite.