A method built on the basis of the toxicity effect of sodium nitrite on luminescent bacterium Vibrio fisheri was developed for determining the toxicity and content of sodium nitrite.Results showed that there was a positive correlation between inhibitory rate of sodium nitrite against luminescent intensity of Vibrio fisheri and sodium nitrite concentration in aqueous solution,with a correlation coefficient ranging within 0.9533-0.9573.The optimal balance time was 15min.Error limit range is 0.6150-2.3466.Inhibitory rate of sodium nitrite against luminescent intensity of Vibrio fisheri was also positively correlated with positive concentration in fruit juice,and the correlation coefficient was between 0.9555 and 0.9970.The optimal balance time was 15min.Error limit range is 0.0852-2.4483.For the establishment of luminescent bacteria toxicity assay lays a foundation.