Hypoxia, a frequent occurring threat in coastal regions, often results in mass mortalities of marine organisms and brings a serious ecological problem. The commercially important Zhikong scallop Chlamys farreri is being under such a threat as the risks of eutrophication and hypoxia have risen in their culture areas. However, little information has been known concing their tolerance to hypoxia and their strategy for survival. In the present study, a 20-day experiment was conducted to determine the effects of hypoxia on the survival, behavior, and metabolism of Zhikong scallop. With the LC 50 for dissolved oxygen (DO) being estimated as 1.8 mg/L, the survival of Zhikong scallop can be greatly challenged even under the moderate hypoxic condition of around 2.0 mg/L DO. The survival rate ranged from 69％ to 59％ when DO dropped from 3.0 to 2.0 mg/L, and it was further reduced to 47％ at 1.5 mg/L DO. In hypoxic conditions, the scallops became significantly active, which may be explained as escape attempts to avoid hypoxic water. To save energy, Zhikong scallop would depress their respiration. However, when DO dropped from 3.0 to 2.0 mg/L, the oxygen consumption rate hardly changed. The upregulation of lactate dehydrogenase activity and the unrepressed phosphofructokinase activity, which often result in the unbalanced cellular homeostasis and energy budget, may account for the observed increase in the mortality rate of Zhikong scallops. In general, Zhikong scallop is sensitive to hypoxia events, though possible escape attempts, depressed respiration, and oxaloacetate-pathway may increase their survival chance.