Sulfur-containing organic compounds, such as mercaptans, are widely distributed in petroleum. A novel refining method for the degradation of mercaptans in petroleum was put forward and investigated by means of gamma-irradiation in this paper. Dodecanethiol (DCT) dissolved in dodecane was employed as the simulation of petroleum. The results showed that the chemical rate constants for the degradation reaction could be described with the first-order rate model. Irradiation with low-dose rate gave rise to a high removal efficiency and a high energy efficiency when the radiation dose was the same. The degradation process was improved greatly by oxygen, and the demanded irradiation dose was reduced markedly. Some chemicals were selected as radio-sensitizers to improve the degradation of dodecanethiol. The degradation processes were enhanced by acetone and carbon tetrachloride, and the degradation efficiencies increased by over 25%, respectively. The main degradation product of dodecanethiol was didodecyl disulfide. Meanwhile, the amount of degradation for dodecane was slight. It would be a potential alternative to degradation of mercaptan compounds in petroleum by gamma-irradiation. (C) 2003 Elsevier B.V. All rights reserved.