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 1.0M KOH electrolyte with 0.1M N2H4, the surfactant-free CuPd nano-alloy only required a potential of 0.648V 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.