A series of WO3-Nb2O5 electrospun heterojunction nanofibers (WN NFs) with different W/Nb molar ratios were fabricated based on an electrospinning technology combined with calcination treatment. The structure and properties as well as the effect of WO3 content on the photocatalytic activity of WN NFs were investigated. The results confirmed that the coupling of WO3 with Nb2O5 resulted a remarkable red shift in the optical response of the heterojunction samples and inhibited the recombination of photoinduced carriers. In the photocatalytic degradation experiment towards methyl orange as the target pollutant, the as-prepared WN NFs exhibited remarkably enhanced photocatalytic activity. Particularly, the WN NFs with W/Nb molar ratio of 15% demonstrated the largest degradation rate, exhibiting a prominent value of 96.4% in 150 min under visible light irradiation. And the kinetic constant was 0.0222 min-1, approximately 13.1-fold and 5.8-fold higher than that of pure Nb2O5 and WO3 nanofibers, respectively.