Combining Cu and Ag in an alloy state holds promise to serve as a tandem catalyst for electrocatalytic CO2 reduction, but is restricted by immiscibility in the bulk. Here, a far-from-equilibrium method is developed to synthesize CuAg alloy by electroreduction of Cu2Ag2O3 under a large cathodic overpotential. The alloy state of CuAg is conducive to the formation of C2+ molecules. A high formation rate of C2H4 of 159.8 μmol cm-2 h-1 is reached on the CuAg alloy nanorods, 2.3 times higher than that on pure Cu.