A water body self-generating electrolytic reduction module is applied to a water body containing oxidizing substances. The water body self-generating electrolytic reduction module includes a self-generating unit and an electrolysis unit. The self-generating unit is coupled to the electrolysis unit. When circulating in a water transmission pipeline, the water body drives the self-generating unit to generate an electric power and deliver the electric power to the electrolysis unit. Upon receiving the electric power, the electrolysis unit performs electrolysis on the water body circulating to the electrolysis unit, so that a reduction reaction occurs to the oxidizing substances in the water body.