The invention relates to a method and a device for treating organic wastewater by virtue of an Electro-Fenton method. The method comprises the following steps: (1) enabling a compound catalyst to be in contact with organic wastewater, so as to adsorb organic pollutants; and (2) carrying out electrolytic treatment on the organic wastewater under an oxygen introduction or aeration condition. By virtue of the method, the compound catalyst is combined with an Electro-Fenton reaction system so as to treat the organic wastewater, the compound catalyst is capable of adsorbing and purifying the organic pollutants in the organic wastewater and generating ferrous ions as a catalyst of the Electro-Fenton reaction system to generate hydroxyl radicals together with hydrogen peroxide generated in an electrolysis system, and the organic pollutants in the organic wastewater are further removed by virtue of oxidization of hydroxyl radicals; meanwhile, the compound catalyst can be repeatedly utilized; and the method can be further combined with measures such as microwaves and photochemistry, so that the treatment effect is improved. By virtue of the method and the device, the organic wastewater is simply and efficiently treated, and the removal rate of the organic pollutants is high.