The effects of experimental parameters on conversion and volatilization ratios in chlorination of UCL₂ to UCl₄ in molten salt was studied. Although the conversion and volatilization ratios were increased with reaction temperature, the optimum reaction temperature range was 600∼700℃ because conversion and volatilization ratios were relatively high and molten salt was scarcely volatilized in the temperature range. Considering utilization of chlorine gas and purity of UCl₄ prepared during experiment, the optimum reaction time was 4 hr. The conversion ratio was increased with quantity of molten salt but determination of the optimum quantity for preparation of pure UCl₄ was required to consider volatility characteristics of impurities contained in reactant and reactant quantity.