A water-soluble fluorescent probe was described for detecting hydrogen peroxide with the naphthalimide derived as fluorophore and boronate moiety as recognition unit. The probe was developed as a turn-on fluorescent chemosensor with fast, high selectivity and sensitivity toward H2O2over other biological reactive oxygen species. What is more, the probe was linear response to H2O2concentration in the range of 2.5×10−8– 3.2×10−5M and lower detection limit down to 12 nM (S / N = 3) was obtained.