Abstract: The interfacial properties of extractants (or surfactants) such as primary amine N ₁₉₂₃ ,trioctylamine (TOA), Tri n octylphosphine Oxide (TOPO),tributyl phosphate(TBP) and sodium dodecyle sulphonate (SDS),were studied at (294±1)K.The interfacial adsorption parameters, c _min , A _I,were calculated respectively.The effect of additives on the interfacial tensions were discussed.These results could be used to explain and assume the extraction rate or mechanism.