Comprehensive SummaryEnergy transformation is imminent, and hydrogen energy is one of the important new energy sources. And oxygen evolution reaction (OER) catalyst with excellent performance is key to improving the hydrogen evolution rate during the electrolysis of water. Single atom alloy (SAA) has garnered significant attention because it partially reduces costs and combines the advantages of both single‐atom catalyst (SAC) and alloy catalyst. Herein, an efficient pyrolysis strategy based on a mixing and drying process is designed to anchor ultra‐small Co cluster particles, combined with Ru single atoms dispersed on nitrogen‐doped ultra‐thin carbon nanosheets (Ru1Co SAA/NC). The prepared electrocatalyst exhibits superior OER activity and superb stability, demonstrating an overpotential of 238 mV for OER with a current density of 10 mA cm‐2 in 0.5 M H2SO4. And we also utilized In‐situ XAS to detect the oxidation state of Ru sites during OER. All in all, this method achieves cost reductions and efficiency improvements through the design of single‐atom alloy catalysts, offering new prospects for the structural transformation of clean energy.This article is protected by copyright. All rights reserved.