This study presents a new method to synthesize a fluorescence probe using an N-doped carbon quantum dot decorated polyacrylonitrile nanofiber (N-CQD@NF) nanocomposite. For this purpose, a combination of the electrospinning technique and a facile hydrothermal method was applied. Gluconic acid and ethylenediamine which are sources for carbon and nitrogen respectively, were used for synthesizing N-CQDs. Characterization of the synthesized fluorescence probe was done using photoluminescence spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy (FT-IR). As Cr(VI) quenches the fluorescence intensity of N-CQD@NF, it can assist in identifying Cr(vi) in environmental samples. Fluorescence probe emission quenching due to a Cr(VI) concentration was observed. It confirmed that Cr(VI) can be detected via employing the fluorescence probe. Using this method and in the optimal conditions, Cr(VI) was determined in a concentration range of 0.15-160.0 mu mol L-1 with a detection limit of 0.05 mu mol L-1. The selectivity of the method for Cr(VI) is high in comparison to other kinds of ions. As a result, it can be concluded that the nanocomposite is an applicable sensitive probe in determination of Cr(VI) in tap and spring water samples.