Ozone sterilization spectroscopy, high efficiency, and no secondary pollution are increasingly being used as an alternative method to chlorine disinfection in drinking water treatment. Ozone is highly unstable in water, and too low a concentration makes it difficult to ensure sterilization effectiveness. Too high a concentration can lead to excessive levels of disinfection byproduct bromate. Therefore, rapid on-site detection of ozone concentration is crucial. To eliminate the tedious operation of preparing reagents and testing processes for users, and improve detection efficiency, based onN. The N-diethyl-p-phenylenediamine (DPD) - potassium iodide method has introduced this ozone reagent.