The influences of some metal ions in seawater treated by Cephlex 100 on metamorphosis , growth and activities of alkaline phosphatase (AKP) and ATPase in mysis and postlarvae of Chinese prawn Penaeus chinensis werestudied. The results showed:Alkaline phosphatase (AKP) and ATPase are two kinds of enzymes that are related to growth and development of animals. Cu2+ , Co2 and Mn2 whose concentrations were 40 , 40 , 20μg ·L -1 respectively could increase the AKP activity significantly in mysis , but higher concentrations decreased the AKP activity. Low Cu2 concentrations (40 -80μg ·L -1) increased the activities of AKP and ATPase significantly ( P < 0. 05) in postlarvae , and Co2 at 20μg·L -1 increased the activities , but Ni2 could not activate these two kinds of enzymes. Because changes of AKP and ATPase activities were relative to the growth directly, the activity of AKP and ATPase could be the indicators for assessment of the physiological condition of the larvae.