is one of the most important seawater fish that cultured in China. In recent years, with the breakthrough of grouper artificial seedling rearing, the farming scale of grouper has expanded rapidly, and the gross of cultured grouper reached 59 534 tons in 2011. The effective prevention and control of virus, , and the effective treatment for harmful water quality factors is the key link in grouper artificial seedling rearing. In traditional pond farming mode, strong oxidizers, such as chloride, iodine and potassium permanganate, have played a significant role in disease prevention and water treatment. In recent years, flatfish industrial farming system, as a mature mode, has been driving the technology intergration of grouper recirculating aquiculture system. The solid oxidants mentioned above were greatly limited in the advanced farming mode, while ozone, a kind of gas disinfectant, not only can remove toxic substance such as nitrite, hydrogen sulfide, ammonia nitrogen and killed pathogenic bacteria effectively, but also will not cause secondary pollution, has been widely applied in water treatment of recirculating aquiculture system in the European Union, the United States, Japan and other developed countries. Although the efficiency and stability of ozone disinfection was widely recognized, its security, especially its toxic effects on the cultured livestock, cannot be ignored. In order to evaluate the ozone disinfection and the potential toxicity of ozone to , the efficiency of ozone at two kind of (0.05 mg/L and 0.30 mg/L) on water treatment, such as removing E. coioide as material, the toxic effects of ozone on the embryonic development and post-embryonic larvae were discussed. Our results demonstrated that 0.30 mg/L, the removal rate of nitrite can be up to 72.29% within 3 h; at the applied ozone dose of 0.05 mg/L and a treatment time of 20min, the in the hatching water that was not disinfected by ozone showed a trend of increase, which was fatal to the . However, the higher embryonic development to some extent, which can caused the number of oil globules increased and led to analosis, collapse and death of the embryo, while the hatching rate ), suggesting the lower concentration of ozone(post-embryonic larvae were more sensitive to ozone compared with the post-embryonic larvae died when they exposed to the lower concentration of ozone (0.05 mg/L) for 24 h. The results of this study provided some important reference data and theoretical basis for using the ozone disinfection technology properly in the process of seedling rearing and cultivating of , and was significant to the sustainable and healthy development of grouper rearing.