Abstract: Er³⁺/Yb³⁺/Li+doped TiO₂colloid and film were prepared by sol-gel method and spin coating method. The optimal preparation scheme for up conversion material was acetylacetone∶C₁₆H₃₆O₄ Ti∶H₂O∶isopropanol∶Er（NO₃）₃·5 H₂O∶Yb（NO₃）₃·5 H₂O∶LiNO₃=1∶3∶9∶70∶0.12∶0.60∶0.15,the dropping rate of water is 10 s/drop,the pH value of the solution is about 2-3,and the sol is transparent and even yellowish. The absorption spectrum is sharp at the peak in the near-infrared region. The visible light transmittance is up to 94.42%,which is 1%-2% higher than ordinary glass. Using the photoelectric conversion efficiency measurement system,after the glass cover plate was coated,the photoelectric conversion efficiency was increased from 16.5% to 17.2%,an increase of 0.7%. The results shown that the film can increase the transmittance of the cover glass,expand the spectral absorption range of the solar cell,and increase its photoelectric conversion efficiency.