The utilization of hydrazine oxidation reaction (HzOR) with a lower thermodynamic oxidation potential has been regarded as an efficient strategy for H2 generation through electrolysis. However, a highly efficient and stable bifunctional electrocatalyst for overall hydrazine (N2H4) splitting was scarce. This work verified promising CuPd nano-alloy as a bifunctional electrocatalys for energy-efficient electrolytic hydrogen production, with hydrazine assistance. It is demonstrated that the CuPd nano-alloy exhibited enhanced electrocatalytic activity for both cathodic and anodic reactions compared to pure Cu and Pd nanocrystals, benefiting from its favorable electronic structure. Under 1.0 M KOH electrolyte with 0.1 M N2H4, the surfactant-free CuPd nano-alloy only required a potential of 0.648 V to achieve the N2H4 splitting (OHzS). The surfactant-free surface maximized exposed active sites, which facilitated the adsorption and desorption of reactants, resulting in enhanced electrocatalytic activity. And working potential for HzOR by surfactant-free CuPd was only 50.4 % compared to the CuPd nano-alloy with surfactant. This work provided an efficient electrocatalyst for OHzS. The enhanced electro-catalytic performances resulting from the electronic structure of alloy and the surfactant-free interface effect have been thoroughly discussed and verified, which would be invaluable for the design of efficient electrocatalysts for H2 production.