Electrocatalytic CO₂ reduction reaction (CO₂RR) into value-added products has been regarded as an effective way to achieve the goal of carbon neutrality. The intrinsic activity of electrocatalysts, as well as the reaction microenvironment, play an important role in improving the conversion efficiency of CO₂. Herein, we report an ionic liquid-functionalized Au/Pd heterostructure as the electrocatalyst for CO₂RR via introducing 1-butyl-1-methylpyrrolidine bis(trifluoromethylsulfonyl)imide ([BMPyrr][NTf₂]) ionic liquid. Au nanoclusters are epitaxially confined on Pd nanosheets in heterostructure, resulting in abundant and well-defined heterointerfaces that work as highly active catalytic sites. Notably, the [BMPyrr][NTf₂] achieves charge redistribution at the Au-Pd heterointerfaces, which helps to stabilize *CO₂˙⁻ intermediate and further reduce the energy barrier of *COOH formation. Furthermore, the [BMPyrr][NTf₂] molecules with high CO₂ adsorption ability is beneficial to construct a CO₂-rich reaction microenvironment at the gas-liquid-solid three-phase interface. The hybrid electrocatalyst exhibits greatly improved CO Faradaic efficiency in a broad potential range and CO partial current density. This work provides a novel strategy for designing robust CO₂RR electrocatalysts via ionic liquid-mediated surface modification.