Abstract: Titanium carbide quantum dots (Ti₃C₂ QDs) were synthesized by etching and hydrothermal method. The fluorescent probe was formed by fluorescence resonance energy transfer (FRET) from Ti₃C₂ quantum dots to rhodamine B (RhB) due to electrostatic interaction. The fluorescence intensity of the proposed probe was quenched caused by the internal filtering effect (IFE) of hexavalent chromium ion Cr(Ⅵ). An "on-off" fluorescent probe was constructed for the sensing detection of Cr(Ⅵ). Under the optimized experimental conditions, fluorescent intensity of the probe was proportional to the concentration of Cr(Ⅵ) in the range of 0.05~500 μmol/L with a detection limit of 0.014 μmol/L (S/N = 3). The constructed fluorescent probe has the characteristics of simple preparation, good stability and selectivity, and high sensitivity for Cr(Ⅵ) detection. The recovery rate for the determination of Cr(Ⅵ) in environmental water samples is 94.3%−104.0%. Therefore, it provides a new method for the rapid and accurate determination of heavy metal ions Cr(Ⅵ) in water.