Abstract: Density, viscosity and surface tension of the two phases in UO2(NO3)2-HNO3-H2O/ 32%(Vol) TBP-kerosene system and H2O/0-32%(Vol) TBP-kerosene system were measured systematically and the temperature coefficient of these physical properties were measured between 25 to 50℃. The methods of measurement are described in details. The results are shown graphically and the empirical formulas derived are given as follows:In UO2(NO3)2-HNO3-H2O/32%(Vol) TBP-kerosene system:Density of organic phase at 25℃ and t℃P25 = 0.819 + 1. 34×10-3Cu + 0.027CH. (Cu: uranium concentration, in g/1, CH: nitric acid concentration in N)ρt = ρ25l-9.1×10-4(t-25). Density of aqueous phase at 25℃ and t℃ρ 25 = 0.999 + 1. 35×10-33Cu+0.032CH-8. 3×10-6-sCuCH. ρ25- ρt=(3.3+0.66CH+8.8×10-3Cu+2×10-3CuCH)×10-4(t-25). Viscosity of organic phase at 25℃ and t℃η25= 1.768 + 0. 233(1- e-3.32cH)e-0.0293cu + 7.66×10-3Cu + 3. 63×10-5Cu2 Surface tension of organic phase is independent of uranium and nitric acid concentrations and is a function of temperature only.Surface tension of aqueous phase at 25℃ and t℃Interfacial tension between organic and aqueous phase is, shown in fig. 7 and its temperature dependence is given byIn H2O/0-32%(Vol) TBP-kerosene system: Density of organic phase(C: volume fraction of TBP in kerosene, t~25-45℃) Viscosity of organic phase at 25℃ and t℃The accuracy of data and availability, of empirical formulas is discussed. These empirical formulas can describe better the physical properties of two phases under various compositions and temperatures than those given in the literature.