Abstract: Material of grapheme quantum dots was dropped on the surface of glassy carbon electrode to form its film, and nitrite (NO₂^-) electrochemical sensor was prepared. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) were utilized to characterize grapheme quantum dots (GQDs). Meanwhile, electrochemical behavior of nitrite was researched by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and current-time curve (I-T) on the surface of modified electrode. The experimental results show that electrochemical sensor exhibits a good electrocatalysis to NO₂^- and possesses a broad linear range in 1~29 μmol/L with detection limit of 3.33×10-7 mol/L (S/N=3). The electrochemical sensor shows the characteristics of wide detection range, low detection limit and good stability.