Hydrogen peroxide is a promising solar fuel and widely used in many industrial processes. Here we report on a new basis for clean energy storage, generating H2O2 from H2O and O-2 by organic photocatalysis. In this study, we construct an all-solid-state Z-scheme heterojunction (PIx-NCN) by assembling perylene imides (PI) on g-C3N4 nanosheets (NCN), where x is a percentage weight ratio of PI to NCN. PIx-NCN exhibits significant enhancement in photocatalytic production H2O2, and the maximum enhancement was observed for PI5.0-NCN. It was shown that PI can change H2O2 generation from single-channel to two-channel. Specifically, photoexcitation of the PI moieties transfers their conduction band electrons to the valence band of NCN, resulting in enhanced charge separation. Thus, more electrons are available to reduce O-2, producing more H2O2. More importantly, the holes in the valence band of PI moiety have more positive potential (2.08 V) than those of NCN (1.63 V), which can oxidize OH- to form center dot OH (1.99 V) and transform to H2O2 via the second channel. Therefore, for PIx-NCN, the photogenerated electrons and holes can be separated into two different phases, helping spatially isolate the oxidation and reduction reaction sites, and thus minimizing the catalytic deactivation.