In order to verify the feasibility about down-conversion materials ap plied in photovoltaic devices and examine the optical properties of KLa0.90Nb₂O₇:Eu³⁺ which closely related to the pre paration conditions, an experimental research is completed in this framework.The formation of lamellar perovskite compound KLa0.90Nb ₂O₇:Eu³⁺ which serves as a novel down-converter was accomplished by a conventional solid-state reaction method. Diverse preparation conditions,doping concentration of rare-earth ion,calcination temperature and calcination durati on, are brought into the experimental respectively.The structure, morphology and optical properties of the product ha ve been characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM),ultraviolet-visible spect ra (UV-Vis) and fluorescence spectrophotometer, respectively.The XRD patterns indicate that KLa0.90Nb 2O₇:Eu³⁺ belongs to orthorhombic perovskite system, and a little impurity phase of EuNbO_4is detected .The appropriate cal cination temperature is 1150℃,and duration is 12h and the preferable doping concentration of Eu³⁺ is 5% when it come s to the photoluminescence intensity which is taken into consideration within photovoltaic devices.The photoluminescence spec tra depict that the emission peaks of KLa0.90Nb₂O₇:Eu³⁺ are 578nm,592nm and 614nm,respectively,unde r the excitation wavelength 363nm.Additionally, KLa0.90Nb₂O₇:Eu³⁺ can be availably applied in photovoltaic devic es to increase the power conversion efficiency and enhance the durability of PV modules, particularly in Si-based solar cells, sin ce its layered structure being available in thin film deposition.