At present, the main bottleneck that restricts the application of rare earth luminescent materials is the lower luminescence intensity of materials. Based on the unique local surface plasmon resonance (LSPR) of MoO_{3  −  x}, we developed new MoO_{3  −  x}  /  YF₃  :  Eu^3  + composites with strong luminescence. The composites possessed stronger luminescent intensity than individually dispersed YF₃  :  Eu^3  +, exhibiting the MoO_{3  −  x}  /  YF₃  :  Eu^3  + composites, which could be used as highly efficient imaging materials. It is proposed that the ultraviolet-excited LSPR of MoO_{3  −  x} is the primary reason for the enhanced luminescence of YF₃  :  Eu^3  +. Meanwhile, the plasmon-enhanced luminescence can be partly absorbed by the MoO_{3  −  x} particles to re-excite its higher energy electrons, thus leading to the selective boost luminescence intensity of MoO_{3  −  x}  /  YF₃  :  Eu^3  + composites. We give insight on the development of plasmon-sensitized luminescence materials.