Abstract: Environmental stresses or plant hormones trigger the production and accumulation of H2O2, a reactive oxygen species, which regulates stomatal movement, growth and development, senescence and stress resistance. To study the signaling and biological function of H2O2, methods to detect H2O2 concentration and variety are necessary. In this study, we compared three H2O2 detection methods — confocal microscopy of fluorescent probes, DAB staining and spectrophotometry — for specificity, sensitivity,quantifiability , time of use, and cost. This work may be helpful in finding anoptimal H2O2 detection method for related research.