Artificial　photosynthesis　for　high-value　hydrogen　peroxide　(H2O2)　through　a　two-electron　reduction　reaction　is　a　green　and　sustainable　strategy.　However,　the　development　of　highly　active　H2O2　photocatalysts　is　impeded　by　severe　carrier　recombination,　ineffective　active　sites,　and　low　surface　reaction　efficiency.　We　developed　a　dual　optimization　strategy　to　load　dense　Ni　nanoparticles　onto　ultrathin　porous　graphitic　carbon　nitride　(Ni-UPGCN).　In　the　absence　and　presence　of　sacrificial　agents,　Ni-UPGCN　achieved　H2O2　production　rates　of　169　and　4116　mu　mol　g(-1)　h(-1)　with　AQY　(apparent　quantum　efficiency)　at　420　nm　of　3.14%　and　17.71%.　Forming　a　Schottky　junction,　the　surface-modified　Ni　nanoparticles　broaden　the　light　absorption　boundary　and　facilitate　charge　separation,　which　act　as　active　sites,　promoting　O-2　adsorption　and　reducing　the　formation　energy　of　*OOH　(reaction　intermediate).　This　results　in　a　substantial　improvement　in　both　H2O2　generation　activity　and　selectivity.　The　Schottky　junction　of　dual　modulation　strategy　provides　novel　insights　into　the　advancement　of　highly　effective　photocatalytic　agents　for　the　photosynthesis　of　H2O2.