Abstract: The effects of concentrations of HNO3,HF, UO2 2+ ion and C2H5OH on reduction yields of U(Ⅵ) and precipitation yields of UF4 at 30±5℃ by using ethanol as a reductant are investigated. Satisfactory results are obtained with a 300W "Ga-lamp", the spectrum of which matched the absorption spectra of uranyl nitrate in HNO3-HF solution. When reaction time > 30 min, for 0.023M UO2(NO3)3 -0.023M HNO3-0.3M C2H5OH-0.15M-HF system, about 100% of reduction yield of U(Ⅵ)and more than 90% of precipitation yield of U(Ⅳ) are obtained.