In this study, a hierarchical Bi2O3/TiO2 fibrous composite was in-situ fabricated on an electrospun TiO2 nanofiber at ambient temperature. In the Bi2O3/TiO2 composite, S-scheme electron migration occurred between Bi2O3 and TiO2. In the photocatalytic degradation of phenol under simulated sunlight, the as-prepared Bi2O3/TiO2 nanofibers considerably outperformed Bi2O3 nanoparticles and TiO2 nanofibers. This improvement is contributed by maintaining and effectively utilizing the useful carriers and consuming the useless holes and electrons, realized by the S-scheme heterojunction and hierarchical structure. This study also provides an alternative design fashion for photocatalysts. (C) 2020 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.