The equations for the concentration of metallic ions in the electroless plating solution have been derived. They are used to predict the effect of plating para- meters(i.e. pH, the concentration of ethylenediaminetetraacetic acid disodium salt (Na2EDTA) and plating temperature) on membrane composition in Pd‒Ag electroless plating theoretically. The experiments have shown that more palladium was deposited as the concentration of Na2EDTA and pH was increased, while the temperature was decreased.