The removal of ammonia nitrogen (NH 4 + -N) and bacteria from aquaculture wastewater holds paramount ecological and production significance. In this study, Pt/RuO 2 /g-C 3 N 4 photocatalysts were prepared by depositing Pt and RuO 2 particles onto g-C 3 N 4 . The physicochemical properties of photocatalysts were explored by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-vis diffuse reflectance spectrometer (UV-vis DRS). The photocatalysts were then applied to the removal of both NH4+-N and bacteria from simulated mariculture wastewater. The results clarified that the removals of both NH 4 + -N and bacteria were in the sequence of g-C 3 N 4 < RuO 2 /g-C 3 N 4 < Pt/g-C 3 N 4 < Pt/RuO 2 /g-C 3 N 4 . This magnificent photocatalytic ability of Pt/RuO 2 /g-C 3 N 4 can be interpreted by the transfer of holes from g-C 3 N 4 to RuO 2 to facilitate the in situ generation of HClO from Cl - in wastewater, while Pt extracts photogenerated electrons for H 2 formation to enhance the reaction. The removal of NH 4 + -N and disinfection effect were more pronounced in simulated seawater than in pure water. The removal efficiency of NH 4 + -N increases with an increase in pH of wastewater, while the bactericidal effect was more significant under a lower pH in a pH range of 6-9. In actual seawater aquaculture wastewater, Pt/RuO 2 /g-C 3 N 4 still exhibits effective removal efficiency of NH 4 + -N and bactericidal performance under sunlight. This study provides an alternative avenue for removement of NH 4 + -N and bacteria from saline waters under sunlight.