The synergistic degradation of landfill leachate was performed by γ-rays irradiation and additive of hydrogen peroxide (H2O2). Effects of absorbed dose, the concentration of H2O2 and initial pH on irradiation degradation efficiency were studied. Ultraviolet-visible spectrometry (UV-VIS), chemical oxygen demand (CODCr) and turbidity were used to monitor the concentration of contaminants in landfill leachate, respectively. The results indicated that the improvement of irradiation degradation efficiency was observed when irradiation was carried out combined with additive of H2O2. When the initial pH was 3, the concentration of H2O2 was 10 mmol/L and absorbed dose was 40 kGy, the removal of CODCr and turbidity was up to 44.3% and 98.3%, respectively. It was considered that the concentration of H2O2 and initial pH is vital in the processing of landfill leachate treatment by γ-rays/H2O2.Cited