Electrochemical nitrogen reduction reaction (NRR) under ambient conditions is highly desirable to achieve sustainable ammonia (NH 3 ) production via an alternative carbon free strategy. Single-atom catalysts (SACs) with super high atomic utilization and catalytic efficiency exhibit great potential for NRR. Herein, a high-performance NRR SAC is facilely prepared via a simple deposition method to anchor Au single atoms onto porous β-FeOOH nanotubes. The resulting Au-SA/FeOOH can efficiently drive NRR under ambient conditions, and the NH 3 yield reaches as high as 2,860 µg·h −1 ·mg Au −1 at −0.4 V vs. reversible hydrogen electrode (RHE) with 14.2% faradaic efficiency, much superior to those of all the reported Au-based electrocatalysts. Systematic investigations demonstrate that the synergy of much enhanced N 2 adsorption, directional electron export, and mass transfer ability in Au-SA/FeOOH greatly contributes to the superior NRR activity. This work highlights a new insight into the design of high efficient NRR electrocatalysts by combination of porous metal oxide matrix and highly active single-atom sites.