Abstract: A novel Bi@Bi₄Ti₃O₁₂/TiO₂ plasmonic composite fibers was synthesized in situ by solvothermal method using electrospun titanium dioxide nanofibers as matrix and reactant, and ethylene glycol as reductant. The XRD, SEM, high power transmission electron microscope (HRTEM), XPS, UV-visible diffuse-reflectance spectrum and photoluminescence (PL) spectra were employed to explore the structural and properties of Bi@Bi₄Ti₃O₁₂/TiO₂ composite fiber. The results indicate that when the reaction temperature is lower than 210℃, the Bi₄Ti₃O₁₂ nanosheets on the surface of Bi@Bi₄Ti₃O₁₂/TiO₂ composite fiber become smaller and thicker gradually with the increasing reaction temperature, and a large number of metal Bi nanoparticles are evenly formed. When the reaction temperature is higher than 210℃, not only the nanosheets accumulate and deform, but also the metal Bi on the surface is oxidized to Bi₂O₃. The Bi@Bi₄Ti₃O₁₂/TiO₂ composite fiber showed excellent photocatalytic efficiency for the degradation of Rhodamine B, with a Rhodamine B degradation rate of 97.8% after visible light irradiation for 5 h. Adjusting reaction temperature not only exerts a pivotal effect on the morphological structure and phase composition, but also affects the photocatalytic capability of the Bi@Bi₄Ti₃O₁₂/TiO₂ plasmonic composite fibers. The improvement of visible-light photocatalytic performance of Bi@Bi₄Ti₃O₁₂/TiO₂ composite fiber is mainly attributed to the formation of high-quality heterojunctions between Bi₄Ti₃O₁₂ and TiO₂, the plasma resonance effect of metal Bi, and the synergistic effect of plasma resonance effect and heterojunction.