Abstract: A method for degrading chlorinated-organic pollutant comprises the steps of providing a chlorinated-organic pollutant contaminated medium having at least one chlorinated-organic pollutant of high concentration; adding a biodegradable surfactant into the chlorinated-organic pollutant contaminated medium to enable the chlorinated-organic pollutant of high concentration to reduce surface tension and increase solubility, and makes the chlorinated-organic pollutant of high concentration dissolve in water easily; adding a persulfate (S2O82?) into the chlorinated-organic pollutant contaminated medium; and adding a slag powder into the chlorinated-organic pollutant contaminated medium to produce a plurality of transition metal ions, and the transition metal ions catalyze the persulfate to generate sulfate radical (SO4?. ) to oxidize the chlorinated-organic pollutant of high concentration of the chlorinated-organic pollutant contaminated medium.