Artificial photosynthesis of H2O2 is conceived to be an ideal approach for replacing the industrial anthraquinone method that suffers from hefty energy penalties and environmental toxicity. However, the low concentration of H2O2 resides as the biggest hurdle for industrial production. Herein, with a focus on fabricating high-performance heterogeneous photocatalysts and establishing a highly efficient complex photocatalytic system, we report the preparation of D-π-A-type conjugated porous polymers containing a photosensitizer and redox-active anthraquinone moiety for endowing highly efficient H2O2 production up to 3.0 mmol g-1 h-1. Further, by exploiting the autocatalytic photooxidation feature of benzyl alcohol, •OOH as the key species contributing to H2O2 formation received a substantial accumulation, which stems from the collaboration of the photocatalytic and autocatalytic cycle. Mechanistically, the hydrogen bonding and π-π stacking between the photocatalyst and benzyl alcohol are formed to lower the free energy of the transition states, thus leading to unprecedently high efficiency in photosynthesis of H2O2 up to 140.4 mmol g-1 h-1, with the concentration of 35.1 mmol L-1 and apparent quantum yield of 49%. This work provides critical insights in advancing sustainable energy conversion research.