Herein, a cucurbit[n]uril carbon quantum dots (Q[6]-CQDs) has been synthesized through a one-step hydrothermal method by using cucurbit[6]uril (Q[6]) and p-aminobenzenesulfonamide (SN), which characterized by UV–vis, FL, IR, XPS, XRD and TEM. The 1H NMR spectra clearly showed that the rigid macrocyclic skeleton of Q[6] was retained during the synthesis of Q[6]-CQDs. In addition, the Q[6]@SN complex was confirmed by X-ray crystallography. The particle size of the prepared Q[6]-CQDs is about ∼ 3.3 nm, which emits strong blue fluorescence and has good water solubility. Subsequently, 2,4-dinitrophenol (2,4-DNP) in aqueous solution was identified and detected by the change of fluorescence intensity of Q[6]-CQDs with a detection limit of 0.15 μM (27.62 μg/L), lower than the relevant standard of USEPA (300 μg/L), and the calculated recovery rate was between 98.90 % and 106.20 %, which provides a new analytical approach for the monitoring of 2,4-DNP in water.