In this paper, a novel modified in situ chemical coprecipitation technology was achieved to synthesize LaNbO 4 doped with Tb 3+ phosphors. Among rare earth (La and Tb) coordination polymers were adopted as precursors for the La and Tb oxides sources, and polyethylene glycol (PEG) was introduced to form the hybrid polymeric systems with rare earth coordination polymers. Accompanied with other functional components, the multicomponent hybrid precursors were composed by an in situ coprecipitation process. After the calcination, LaNbO 4 :Tb 3+ phosphors were obtained, whose particle sizes were in the range of 1–3μm characterized by XRD and SEM. The photoluminescence properties of LaNbO 4 :Tb 3+ phosphors were compared to investigate as a function of Tb 3+ ion concentrations, which revealed that these nanophosphors showed a strong visible green emission from 5 D 4 to 7 F 5 at 543nm under ultraviolet excitation. The luminescence of Tb 3+ quenches emission for a charge-transfer-band of NbO43-.