Abstract: The electrochemical process of 4-chlorophenol with graphite rods electrodes under different conditions was studied.The result shows that CODCr degradation rate and dechlorination rate first ascend and then descend with the increase of voltage;exponentially decay with the increase of mass concentration of 4-chlorophenol;and increase with the rise of pH.Alkaline condition is preferred to neutral and acidic conditions in the results of degradation.A solution of 100 mg/L 4-chlorophenol (pH≈12) was electrolyzed at a constant potential of 10 V for 2 hours and the CODCr degradation rate is 52.94% and dechlorination rate is 52.8%.By means of the high energy pulse electron beam produced by a linear accelerator as well as a set of transient absorption spectra recorder,the reaction mechanism of 4-chlorophenol was found to be the function of reactive particles OH·. The intermediate product is OH-adducts under neutral and acidic conditions,while 4-chlorophenol is degraded by both action of OH· and direct oxidation on anode under alkaline condition.Analysis of products shows that the intermediate products are hydroquinone and benzoquinone.