A promising nitrite sensor based on one-dimensional polyoxometalate hybrid nanofibers was prepared and developed by electrospinning of a mixture of poly(vinyl alcohol) and a-K6[P2W18O62]center dot 14H2O (P2W18) onto the surface of an indium tin oxide (ITO) electrode. After thermal crosslinking, the P2W18 hybrid nanofibers are insoluble in aqueous solutions even after a period of 24 hours, which ensures the electrochemical stability of the P2W18 hybrid nanofiber-modified ITO electrode. The cyclic voltammetry results have demonstrated that the P2W18 hybrid nanofiber-modified ITO electrode exhibits excellent electrocatalytic activity toward the reduction of nitrite in acidic solutions. Additionally, long-term stability and reproducibility have been observed.