The invention discloses a surface modification method of ZnS powder. The surface modification method comprises the following steps: stirring oxidized polyethylene powder, deionized water, an emulsifier and other reagents at the normal temperature, heating the mixture and sealing, pressurizing and stirring, keeping pressurization, naturally cooling, adjusting the air pressure to be 0.1-0.5 MPa, stirring the solution until the temperature of the solution is the room temperature, adjusting the pressure to be standard atmospheric pressure, filtering the emulsion, adding ammonia water in the obtained emulsion, adjusting the pH value to be 8.0-9.0, adding the organic modified emulsion in the ZnS powder, stirring the solution, and standing; drying the modified ZnS powder, and naturally cooling the ZnS powder to obtain the surface modified ZnS powder. The modified ZnS powder can be dispersed in a base material well, is high in compatibility, has good antimicrobial, mildew-proof and algae-removing effects in the internal and external wall coating, can be used as a white pigment in the coating and plastics to enhance whiteness, and is high in cohesiveness to bind other inorganic materials; the process is simple, the operation is easy, the preparation process is free of pollution, and the energy-saving and environment-friendly requirements can be met.