NOVELTY - A nano tin oxide-doped solution is prepared by mixing tin salt, fluoride compound and antimonide, dissolving the mixture in deionized water, adding ammonia solution or sodium hydroxide solution while stirring, aging the mixture to obtain precipitate, washing the obtained precipitate with deionized water, dripping hydrogen peroxide solution or oxalic acid, subjecting mixture to reflux heating, subjecting product to hydrothermal reaction, and dissolving the product in deionized water to obtain nano antimony-doped and oxyfluoride tin-doped solution.    USE - Method of preparing a nano tin oxide-doped solution for preparing solution film for low emissivity glass, display equipment, gas sensitive sensor or transparent electrode of solar battery (claimed).    ADVANTAGE - The method prepares product having uniformed grain size without the need for high temperature calcination.    DETAILED DESCRIPTION - A nano tin oxide-doped solution is prepared by:    (A) mixing tin salt and fluoride compound as dopant at a mass ratio of 1:0.1-0.8, dissolving mixture in deionized water, adding ammonia or sodium hydroxide solution to regulate pH value to 6-8, aging the mixture to obtain precipitate, filtering and washing the precipitate, mixing washed deposit and deionized water, dripping hydrogen peroxide solution or oxalic acid at low temperature, subjecting mixture to reflux heating for 2-4 hours, adding dopant fluoride compound, subjecting mixture to hydrothermal reaction at 120-160 degrees C for 20-30 hours, subjecting to centrifuge washing or vacuum suction filtration until the electrical conductivity of the filtrate is smaller than 100 mu S/cm, and dissolving the product in deionized water to obtain nano tin oxyfluoride-doped solution;    (B) mixing tin salt and trichloride antimony as dopant at a mass ratio of 1:0.01-0.05, dissolving mixture in deionized water, adding ammonia or sodium hydroxide solution while stirring to regulate pH value to 6-8, aging the mixture to obtain precipitate, washing separated precipitate with deionized water, dripping hydrogen peroxide solution or oxalic acid at low temperature, subjecting mixture to reflux heating for 3-5 hours, adding dopant fluoride compound, subjecting mixture to hydrothermal reaction at 140-180 degrees C for 44-50 hours, subjecting product to centrifuge washing or vacuum suction filtration washing until electrical conductivity of the filtrate is smaller than 100 mu S/cm, and dissolving the product in deionized water to obtain nano tin antimony oxide-doped solution; and    (C) mixing tin salt, fluoride compound and antimonide as dopant at a mass ratio of 1:0.02:0.1, dissolving the mixture in deionized water, adding ammonia solution or sodium hydroxide solution while stirring to regulate pH value to 6-8, aging the mixture to obtain precipitate, washing the obtained precipitate with deionized water, dripping hydrogen peroxide solution or oxalic acid at low temperature, subjecting mixture to reflux heating for 5-7 hours, subjecting product to hydrothermal reaction at 180-220 degrees C for 120-150 hours, subjecting to centrifuge washing or vacuum suction filtration until the electrical conductivity of the filtrate is smaller than 100 mu S/cm, and dissolving the product in deionized water to obtain nano antimony-doped and oxyfluoride tin-doped solution.    The tin salt is tin nitrate, tin sulfate, tin tetrachloride or stannous chloride. The fluoride compound is ammonium fluoride or hydrogen fluoride. An INDEPENDENT CLAIM is included for use of nano tin oxide-doped solution for preparing solution film comprising spray coating, spin coating or dipping and drawing method nano tin oxide-doped solution to obtain film; and adding tackifier to increase viscosity.