Abstract: The extraction of palladium(Ⅱ) with quaternary ammonium salt N₂₆₃ in n-octane from hydrochloric acid medium has been studied at 25±1℃. The experimental results indicate that the extraction is an anion exchange process: where ACl and (O) represent N₂₆₃ and organic phase respectively. Equation(Ⅰ) takes place at higher acidity but with the lowering of the acidity,equation(Ⅱ) becomes predo-minant.The experimental results also show that the dimer species of Pd(Ⅱ) is formed in the organic phase with the increasing of Pd(Ⅱ)in it.The influences of temperature and added (n-octanol) on the extraction of Pd(Ⅱ) were also discussed.