The invention relates to a processing system and a method for a radioactive nuclear waste organic phase. The processing system comprises a pretreatment unit, a wet catalytic oxidation treatment unit,an electrolytic oxidation treatment unit and an evaporation concentration treatment unit, which are sequentially connected. In the treatment process, the waste organic phase is firstly implemented pretreatments such as mixing, dilution, dosing, stirring and the like by the pretreatment unit, and then the waste organic phase is entered into the wet catalytic oxidation unit and the CODcr in the waste organic phase is degraded, and most organic matters are catalytically oxidized into inorganic substances or macromolecules are catalytically oxidized into micromolecules; the water treated by the wet catalytic oxidation is entered into the electrolytic oxidation treatment unit again for an advanced oxidation treatment, and finally the organic phase is completely converted into an inorganic phaseto thoroughly realize a change of water into oil; because a small amount of radioactive uranium, phosphate radicals, nitrate radicals and the like are contained in the treated water, so that the uranium, the phosphate radicals and the nitrate radicals are recycled by the evaporation concentration processing unit; the technical problems of a nuclear industry for many years and a potential safety hazard of long-term storage of the waste organic phase are solved.