Hydrogen　peroxide　(H2O2)　is　an　environmentally　friendly　reagent,　and　organic　semiconductors　(OSCs)　are　ideal　photocatalysts　for　the　synthesis　of　H2O2　due　to　their　well-defined　molecular　structure,　strong　donor-acceptor　interactions,　and　efficient　charge　separation.　This　review　discusses　the　regulatory　mechanisms　of　functional　group　modifications　in　tuning　the　photocatalytic　performance　of　OSCs,　highlighting　the　relationship　between　functional　group　structure　and　catalytic　performance.　For　example,　electron-regulating　groups,　such　as　cyano　and　halogen,　induce　molecular　dipoles,　facilitating　the　migration　of　photogenerated　electrons.　Fluorine　groups　optimize　the　band　structure　and　prolong　carrier　lifetime　due　to　their　high　electronegativity.　pi-Conjugated　extension　groups,　like　anthraquinone　and　thiophene,　expand　conjugation,　improve　visible　light　capture,　and　stabilize　intermediates　through　redox　cycles.　Hydroxyl　groups　enhance　surface　hydrophilicity　and　promote　H2O　activation,　while　imine　bond　protonation　adjusts　charge　distribution　and　improves　selectivity　and　cycle　stability.　Multi-active　site　functional　groups,　such　as　sulfonic　acid　and　amide,　accelerate　reaction　kinetics　and　inhibit　H2O2　decomposition.　Functional　groups　enhance　light　absorption,　charge　separation,　and　surface　reactions　through　electronic　structure　regulation,　intermediate　adsorption　optimization,　and　proton-electron　transfer.　Future　work　should　integrate　machine　learning　to　identify　optimal　functional　group　combinations　and　develop　green　functionalization　strategies　for　efficient　H2O2　photocatalyst　synthesis.