Abstract: A new liquid membrane system is established with a double carrier(TRPO, a mixture of trialkyl phosphine oxime, and HDEHP, bis-(2-ethylhextyl)phosphoric acid)membrane phase, basic inner aqueous phase and weak acidic waste water phase for the removal of Cd2+ and CN- simultaneously and the direct re-use of the concentrated Cd(CN)42- in plating tanks. In order to describe the matching of the transport rates of Cadmium and Cyanide in this system, a synchronous-transport concept is developed and mathematically presented to be the same form of the liquid membrane transport rate equations of the two transported species. These equations can be used as a guidance for the selection of the optimum operation condition for the separation process.