MoO3/V2O5 heterostructures with high photocatalytic activity in visible light region were synthesized via electrospinning technique and sol-gel process. The morphologies and structures of MoO3/V2O5 heterostructures were characterized by X-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and UV-visible diffuse reflectance spectroscopy. The photocatalytic performances of MoO3/V2O5 heterostructures were evaluated by the photodegradation of methylene blue (MB) under visible light irradiation. The results indicated that heterojunctions between MoO3 and V2O5 were formed when the n(Mo)/n(V) ratio was above 1: 8, and the separation of photogenerated electron-hole pairs on MoO3/V2O5 heterostructures was promoted, which made the decolorization rate of MB by MoO3/V2O5 heterostructures much higher than usage of pure V2O5 nanofibers. The optimum n(V)/n(Mo) ratio of MoO3/V2O5 heterostructures was found to be about 1 : 6 and the decolorization rate of MB could be reached 97.24%. In addition, the photocatalytic mechanism of the MoO3/V2O5 heterostructures was further analyzed and discussed.