Ag2S quantum dots decorated TiO2 nanosheets with highly reactive {001} facets exposed were grown on carbon fibers by hydrothermal technology and successive ionic layer adsorption and reaction method. The ternary CFs-TiO2-Ag2S heterostructure exhibits excellent photoelectrochemical protection performance for the coupled 304 stainless steel. Ag2S quantum dots with narrow band gap enhance the sunlight harvest of the hybrid. The carbon fibers act as transmission channels for the photo-induced electrons that facilitate the photogenerated carrier separation. Schottky barrier formed in the heterostructure interface and the increased inner electric field promote the electron dissociation and migration from the hybrid semiconductor to the coupled metal, resulting in enhancement of photoelectrochemical protection of the 304 stainless steel.