The characteristic of the o-chlorophenol degradation by pulsed high voltage discharge was investigated in present work.The concentration of o-chlorophenol declined faster by a shortening distance

increasing peak voltage or frequency.A degradation efficiency of 98.7% for o-CP is achieved after degradation for 30 min under the conditions of 2 cm of the electrode distance

30 kV of the peak voltage and 150 Hz of the frequency.It was found that the discharge form was determined not only by the peak voltage and the electrode distance

but also by the salt content in the solution. The increase in salinity could cause a transition from spark discharge to stream discharge and then to corona discharge. The concentration of o-chlorophenol declined faster in the spark and stream discharge than in the corona discharge. The degradation of o-chlorophenol is attacked by hydroxyl radical to form 2-chloro- hydroguinone.The later is oxidized to 2-chloro-benzoquinone.Therefore

the ring is opened to form simple organic acids such as metacetonic acid

oxalic acid

acetic acid and formic acid.