Activated carbon (AC) with high porosity and surface area as a catalyst carrier can enhance the catalytic activity and stability of metal nanoparticles with well dispersion to avoid aggregation. Herein, silver molybdenum oxysulfide (AgMoOS) nanoparticles supported by activated carbon with different porous sizes were synthesized through a facile method for photocatalytic H2 evolution reaction and pollutants reduction. The highest H2 evolution of 338.9 µmol/h was obtained by microporous AC-supported AgMoOS ([email protected]) under visible-light irradiation using Na2S/Na2SO3 as a hole scavenger reagent. Likewise, 76.9% of the 4-NP reduction is achieved by in-situ generated proton within 160 min. AC could lower the recombination rate of photo carriers due to its pore channels. Under the dark condition, 10 mg [email protected] completely reduced MB, MO, RhB, 4-NP, and Cr6+ within 4, 4, 9, 9, and 12 min, respectively. This excellent catalytic activity is due to a good dispersion of AgMoOS nanoparticles on AC-1, electron hopping transport of Mo4+→ Mo6+ ions, and surface oxygen vacancy. [email protected] catalyst also exhibits good stability and efficiency that provides a practical catalytic application to reduce chemical pollutants and environmental remediation.