The invention discloses a method of treating radioactive wastewater by a UV coupling Fenton method; the method comprises: adjusting pH of radioactive wastewater, charging into a Fenton oxidative reaction chamber, allowing the wastewater to flow sequentially into three oxidizing compartments of the Fenton oxidative reaction chamber, adding a solid catalytic aid into each oxidizing compartment, and turning on a first ultraviolet lamp tube to treat the radioactive wastewater; charging the treated radioactive wastewater into a coagulating sedimentation tank, adding a coagulant for solid-liquid separation, charging effluent into a filter barrel having a filter membrane inside to perform filtering, and turning on a second ultraviolet lamp tube in the filter barrel so as to finish the treatment of the radioactive wastewater. The UV coupling Fenton method is used herein to treat organic wastewater; the solid catalytic aid is added so that the Fenton method has improved depredating efficiency and effect for organic matters; radioactive elements and residual organic matters in the organic wastewater are removed through secondary degrading and filter-absorbing actions of the filter membrane and ultraviolet source, and the radioactive organic wastewater is thoroughly treated.