Polyphenol oxidase(PPO) was extracted from cuttlefish ink with 0.05mol/L pH 7.2 sodium phosphate extraction buffer. The crude extract was fractionated with solid ammonium sulfate of 30% - 80% saturation. After dialysis and concentration, The enzyme solution was purified by DEAE-Sepharose CL-6B column chromatography and a 12.2 fold purification of PPO was obtained. Cu2+ and Pb2+ at level of mmol/L inhibited PPO activity while Na+ , K+ , Mg2+ and Ca2+ have little effect on PPO activity, however PPO was apparently activated by Cu2+ at 20umol/L. PPO activity was strongly inhibited by HSO3 ~ and the activity was completely inhibited at 10mmol/L. Cl- , Br~ , I- and SO42- have almost no effect on PPO activity.