AbstractPhotocatalytic H2O2 evolution via two‐electron oxygen reduction is a promising path for renewable and on‐the‐spot H2O2 production compared with the traditional anthraquinone method. However, the efficiency of photocatalytic production of H2O2 is usually very low. Herein, P‐doped carbon nitride loaded with ruthenium single atoms and clusters (Ruatom/P‐CN) is reported as an efficient photocatalyst for H2O2 production. The yield of H2O2 over Ruatom/P‐CN (385.8 mmol g−1 h−1) is about 4.3 times higher than that of P‐CN (88.9 mmol g−1 h−1) and 3.6 times higher than that of ruthenium nanoparticles loaded P‐CN (105.9 mmol g−1 h−1). Further mechanistic study indicates that the presence of Ru in the form of single atoms and clusters not only improves the separation efficiency of photogenerated carriers and inhibits the recombination of photogenerated electron‐hole pairs, but also increases the reactive sites of this catalytic system. This study breaks through people‘s understanding that precious metal loading is not conducive to H2O2 selectivity and provides a new way to prepare low‐metal loading, high‐activity photocatalysts for H2O2 production.