Abstract: Being a common pollutant in aquaculture system,nitrite is a significant factor that affects water ecological environment.High concentration of nitrite can be toxic and fatal in aquatic animals such as fishes,mollusc and crustaceans.Nitrite was discussed in the paper from the following four aspects,the mechanism of the production,toxicity,dangers and method of governance.We hope the paper could provide scientific basis for detoxification to nitrite,improvement of economic benefits in aquaculture industry and restoration to ecological balance.