Abstract: The partition equilibria for the following systemsMn²⁺/(Na₂·H₂)SO₄(0.1M)/HDEHP-Kerosenc and Mn²⁺/(Na₂·H₂)SO₄(0.1M)/(HDEHP-TOPO)-Kerosene have been studied at 25℃. The extraction reactions were found to be   respectively.The effects of temperature and additives, TBP, P₃₅₀, TOPOon the extraction of Mn(Ⅱ) from 0.1M (Na₂,H₂)SO₄ with the solution of HDEHPin kerosene have also been investigated. The synergism of the additives has been found to decrease in the order TOPO>P₃₅₀>TBP. By using the temperature coefficient method, ΔH° of ( i ) was calculated to be-2.90 Kcal/mol in the range of 20-60℃. Thus the extraction of Mn(Ⅱ) from aqueous solution with HDEHPis an exothermic reaction. The increase of distribution ratio Dwith temperature, may be partly due to the increase in pHof the sulfate medium.