Abstract: The effects of temperature, the concentrations of HNO₃ and the concentrations of Pu(from 0.35 g/L to 11.1 g/L in the equilibrated aqueous phase) on the distribution ratio of Pu (D (Pu)) between HNO₃ and 30%TBP-dodecane were studied. The results show that at 25℃, D (Pu) reduces with the concentration of Pu with >1.5 mol/L HNO₃ and hardly changes with 0.4 mol/L HNO3. Within 25-60 ℃, with 1.34-3.80 g/L Pu, and 1.5 mol/L and 3.0 mol/L HNO₃ in the equilibrated aqueous phase, D (Pu) increases with the temperature with a highest growth percentage of 39.4%. At 25 ℃, D (Pu) by 30%TBP-dodecane extraction is higher than the corresponding calculated value by 30%TBP-koresene extraction with 1.5 mol/L，3.0 mol/L and 4.5 mol/L HNO₃; however, similar D (Pu) values are obtained in the two systems with 0.4 mol/L HNO3.