The radiolytical degradation of 3-chlorophenol (3-CP) in aqueous solution was investigated using gamma-radiation and gamma-radiation/hydrogen peroxide (H2O2) combined process. The effect of absorbed dose, initial concentration of 3-CP and addition of H2O2 on pollutant degradation, dechlorination and the degree of mineralization was studied by measuring the removal efficiency of 3-CP, the variation of total organic carbon (TOC), the dechlorination rate, and the absorbance spectrum of vis-UV. The kinetics of 3-CP degradation was also discussed. The results showed that when 3-CP concentration was 10 mg x L(-1) and the absorbed dose was 2 kGy, the dechlorination rate reached 100%, the TOC removal efficiency was 53%; when the absorbed dose increased to 8 kGy, 3-CP could be completely mineralized and the TOC removal efficiency reached 100%. The radiolysis of 3-CP could be described by one-order reaction kinetics, there existed synergic effect for combined process of gamma-irradiation/hydrogen peroxide for 3-CP degradation. The rate constant of 3-CP degradation for gamma-radiation and gamma-radiation/hydrogen peroxide combined process was 0.279 h(-1) and 0.542 h(-1), respectively.