The purpose of this study was to evaluate the potential of electron beam to decompose chloramphenicol(CAP)in aqueous solutions.At the absorbed dose of 15 kGy,the decomposition rate of CAP was 95.24%.The degradation of CAP under electron beam irradiation followed pseudo-first-order kinetics.Redox reactions of CAP aqueous solutions with hydroxyl radicals(·OH),hydrated electrons(e-aq)and hydrated atoms(·H)were studied.The increase of the additives would result in the decrease of the degradation efficiency.The concentration of Cl-and NO3-in aqueous solution increased after electron beam irradiation.On the basis of the experimental results,a photocatalytic mechanism was discussed.The rate constant for reactions of ·OH and CAP was 9.36×107 L/(mol·s)and for reaction of e-aq and CAP was 7.33×107 L/(mol·s).·OH was supposed to play the key role in the radiation system of aqueous solution.Other free radicals like e-aq and ·H could also initiate the degradation.