Benzoindoles containing hydroxyl (DHB) was synthesized and applied for the fluorescence response to hydrogen peroxide (H2O2), and the effects of solvents and pH values were studied on the detection system. Under the optimum conditions, the increased concentration of H2O2 caused the fluorescence signal of DHB shifted from 580 nm to 560 nrn, and that at 560 nm enhanced gradually in the linear range of 0.1 mM to 1.2 mM with detection limit of 0.72 M. This method can be used for the determination of trace concentration of H2O2 in disinfectant and tapwater samples with ...