NOVELTY - An active component conversion of rare-earth ion pair-doped nano fluoride is provided to adopt micro-emulsion method, and rare-earth ions are doped. Active constituents broadband sensitizing absorption and light down-conversion material are provided on the absorption to visible light material in the visible light wave band and light up-conversion material is provided on infrared light wave band. The polymer base material is provided, optical active component is dispersed, and bulk polymerization or spin-coating method is adopted, to obtain fluoride nano particles.    USE - Preparation of fluoride nano particles.    ADVANTAGE - The fluoride nano particles is efficiently prepared.    DETAILED DESCRIPTION - An active component conversion of rare-earth ion pair (Er3+-Yb3+, Pr3+-Yb3+, Tm3+-Yb3+, Tb3+-Yb3+, Ho3+-Yb3+)-doped nano fluoride is provided to adopt hydrothermal solvothermal and micro-emulsion method to synthesize nano particles, and rare-earth ions are doped to the nano particles. The rare-earth ions are doped in the inert rare-earth elements of alkaline earth metal fluoride-strontium fluoride, calcium fluoride, rare-earth fluoride and sodium rare-earth fluoride. The rare-earth is lanthanum or yttrium. Active constituents broadband sensitizing absorption and light down-conversion material are provided on the absorption to visible light material in the visible light wave band and light up-conversion material is provided on infrared light wave band. The different sensitizing ions is added to the active component and doped with rare-earth ions to improve conversion efficiency of light conversion material. The polymer base material is provided, nano particles must be matched with refractive index of base material to reduce or to eliminate the optical dispersion caused by difference of refractive index. The optical active component is dispersed in the polymer monomer or its solution, bulk polymerization or spin-coating method is adopted to prepare polymer-based composite material, distribution of composite material particle and optical property of light conversion of composite material are represented, to obtain fluoride nano particles.