A series of semimetal Bi-doped carbon fibers (Bi/CFs) were prepared by electrospinning-calcined polyacrylonitrile technique and characterized by XRD, SEM, EDS, XPS and UV-Vis DRS spectra to probe the morphology, structure and optical properties. Then, the Bi/CFs hybrids as photocatalysts were investigated the photocatalytic performances for degradation of representative environmental contaminants (Congo red dye and antibiotics sulfanilamide) under visible light irradiation (lambda > 420 nm). In different compositions, the photocatalytic efficiencies have followed the order as Bi (5%)/CFs > Bi (10%)/CFs > Bi (1%)/CFs > polyacrylonitrile carbon fibers, that was mainly for the surface plasmon resonance effect of semimetal Bi, which made Bi/CFs hybrids had high light-harvesting properties and effective separation abilities of photogenerated carriers. According to the results of optical performance and the scavengers trapping experiments, the feasible photocatalytic mechanism was deduced. This study provided semimetal Bi, a new plasmonic co-catalyst, as a well substitute for Au and Ag noble metal to be a promising potential for environmental contaminants treatment.