Abstract:The interaction between malachite green (MG) and cucurbit [7]uril (CB7) had been studied based on fluorescence and 1 H NMR spectroscopic results. The interaction mechanism was also discussed concretely based on 1 H NMR results. The fluorescence intensity of malachite green (MG) enhanced strongly and a slight red shift was observed at the maximum emission peak when added into cucurbit [7]uril. We had found that the formation of the complex at a 1:1 complex stoichiometry and the association constant was calculated by applying a deduced equation. The thermodynamic parameters such as ΔH and ΔS values were obtained according to Van't Hoff equation, respectively. We prepared the solid inclusion complex from co-evaporation method and characterised it by 1 H NMR、 IR. For the efficient detection of malachite green, the limit of detection was 4.2 × 10 -8 mol·L -1 from our experiments which will make our method applied to detect the malachite green in sewage effectively. Keywords