Abstract: The extraction kinetics and mechanism of palladium (Ⅱ) from chloride medium with trioctylamine (TOA) were studied by means of PVC-membrane Pd(Ⅱ) ion selective electrode and stationary interface stirring cell. The experimental results showed that the extraction process is controlled by the following reactions,(这里有图片198704-296-1.gif)where (i) and (o) represent the interface and the organic phase, respectively. The values of k₁, k_-2and k₂/k_-1were calculated by computer. The influences of the temperature, acidity and added substance (n-octoh) in the organic phase on extraction rate are also discussed.