Abstract: The preparation of ¹⁰³Pd-¹¹⁰Ag^m alloy membranes was the basis for the production of ¹⁰³Pd-¹²⁵I composite sources. Taking ¹⁰³Pd and ¹¹⁰Ag^m as trace elements, the method of nonelectrolytical plating was chosen to prepare the alloy membrane. A γdetector and electron microscope (SEM) were used for quantitative and qualitative analysis, respectively. The pretreatment of the support before the preparation of Palladiumsilver composite membranes was discussed in detail. It was found that when the concentration of PdCl₂ was between 0.5 and 2.0 mmol/L the result was good. The effects of various factors were investigated，including the proportion of Pd and Ag, the concentrations of the total metal，ammonium hydroxide hydrazine and ethylenediaminetetraacetic acid, temperature, the time, and the rotation speed. By improving the reaction conditions the alloy membrane with metallic luster was obtained. Besides, the presence of Pd and Ag was observed in the alloy membranes by qualitative analysis.