Abstract: Sodium hypochlorite has been used as bactericidal agent in many industries,but it is the first time using it as antiseptic of sewage in industry test of oilfield.This paper introduced technical principle that sodium hypochlorite produced by electrolyte brine was directly used for sewage disposal as well as application in water disposal plant of Dagang oilfield.Experiments on the concentration of sodium hypochlorite as disinfectant and corrosive nature of injection equipment have been done too.It is proved that bactericidal continuity is better,and though after sterilization corrosion rate of sewage improved,the operation is safe.