A one step electrospinning approach was utilized for the preparation of polyaniline (PANI) modified titanium dioxide/polyacrylonitrile (PAN) composite nanofiber using a mixture of dimethylformamde (DMF) and N-methyl-2-pyrrolidone (NMP) as solvents. Several techniques were carried out to characterize the resulting electrospun fibers including SEM, FTIR, XRD, TGA and DRUV-Vis absorption spectroscopy. The later method showed an optical band gap shifting for polyaniline modified titanium dioxide/polyacrylonitrile composites in comparison to unmodified one. Due to these optical absorptions, the fibers can be considered promising candidates as visible light photocatalysts to generate more electron-hole pairs. Photodegradation was accomplished using methyl orange (MO) as a model organic pollutant. The degradation of MO, extremely increased using photocatalysts which contained PANI and decolorization in the presence of visible light achieved up to 90% in less than 60 min in comparison with the neat nanofibers (about 10%). This advantage promises a bright future for these fibers as useful photocatalysts. The effect of reaction parameters such as photocatalyst dose, concentration of the starting substrate solution and pH were studied and photocatalytic kinetics was investigated. The stability of photocatalyst was also investigated. The photocatalyst retained 87% of its initial activity after 10 replicate uses. (C) 2016 Elsevier B.V. All rights reserved.