The methods for improving Epichlorohydrin process was investigated by carrying out experiments on hypochlorination reaction, from which dichlorohydrin is produced by reacting with allyl chloride and chlorine. As the recycle water from PVC plant was used instead of industrial water for reaction, the effect of recycle water on the reaction yield was studied. It was shown from this experiment that the recycle water rarely affected on the ratio between products. TCPA, which was almost of byproducts, could be removed before purification process using "extractant A". This could prevent additional side reaction by TCPA and reduced energy to separate it in purification part. The change of product yield was observed as the chlorine gas addition decreases which reacted with allyl chloride. It seems that the yield of major products didnt change almolt, but the byproducts showed rather reduced trend with decreasing chloring gas.