The synthesis of Pd-Ag alloy nanowires in nanopores of porous anodic aluminum oxide (AAO) template by electrochemical deposition technique was reported.Pd-Ag alloy nanowires with 16%-25% Ag content are expected to serve as candidates of useful nanomaterials for the hydrogen sensors.Scanning electron microscopy (SEM) and energy dispersed X-ray spectroscopy (EDX) were employed to characterize the morphologies and compositions of the Pd-Ag nanowires.X-ray diffraction (XRD) was used to characterize the phase properties of the Pd-Ag nanowires.Pd-Ag alloy nanowire arrays with 17.28%-23.76% Ag content have been successfully fabricated by applying potentials ranging from -0.8 to -1.0 V (vs SCE).The sizes of the alloy nanowires are in agreement with the diameter of AAO nanopores.The underpotential deposition of Ag~+ on Pd and Au plays an important role in producing an exceptionally high Ag content in the alloy.Alloy compositions can still be controlled by adjusting the ion concentration ratio of Pd~(2+) and Ag~+ and the electrodeposition processes. XRD shows that nanowires obtained are in the form of alloy of Pd and Ag. The synthesis of Pd-Ag alloy nanowires in nanopores of porous anodic aluminum oxide (AAO) template by electrochemical deposition technique was reported. Pd-Ag alloy nanowires with 16% -25% Ag content are expected to serve as candidates of useful nanomaterials for the hydrogen sensors. Scanning electron microscopy (SEM) and energy dispersed X-ray spectroscopy (EDX) were employed to characterize the morphologies and compositions of the Pd-Ag nanowires. X- ray diffraction (XRD) was used to characterize the phase properties of the Pd-Ag nanowires. Pd-Ag alloy nanowire arrays with 17.28% -23.76% Ag content have been successfully fabricated by applying potentials ranging from -0.8 to -1.0 V (vs SCE). These sizes of the alloy nanowires are in agreement with the diameter of AAO nanopores. The underpotential deposition of Ag ~ + on Pd and Au plays an important role in producing an exceptionally high Ag content in the alloy. Alloys compositions can still be controlled by adjusting the ion concentration ratio o f Pd ~ (2+) and Ag ~ + and the electrodeposition processes. XRD shows that nanowires obtained are in the form of alloy of Pd and Ag.