Abstract: The combination of solar disinfection and photocatalysis technology presents a viable solution for eliminating harmful pathogenic microorganisms from water. However, some photocatalysts (e.g., zinc oxide-based composites) are susceptible to pH-dependent dissolution in water, which can result in the loss of photocatalysts and additional environmental pollution. To obtain zinc oxide-based composites with low dissolution and high antibacterial efficiency for photocatalytic water disinfection, we prepared MoS₂/ZnO@CS composites via a precipitation method to encapsulate chitosan (CS) around MoS₂/ZnO. The amino groups in the CS molecules act as storerooms for hydrogen ions, which inhibits the dissolution of zinc oxide. In addition, the MoS₂/ZnO@CS composites exhibit high production of reactive oxygen species (ROS) and broad-spectrum antibacterial activity under simulated solar irradiation (0.1 W·cm⁻²). This makes it an excellent antibacterial agent for solar disinfection in water treatment.