[Objective] The aim was to study the effect of bensulfuron-methyl herbicide on acute toxicity and genetics toxicity of Danio redo. [ Method] Median lethal concentration was calculated by acute toxicity test, and analyzing the herbicide whether existing in potential toxicity to aquatic organisms or not. Based on the study of acute toxicity, genetics toxicity was carried out, by calculating the micronucleus rate to judge bensulfuron-methyl herbicide whether existing in potential toxicity or not. [ Result ] The LD5o （24 h and 48 h） of bensulfuron-methyl herbicide are 0.698 ml/L and 0.637 ml/L respectively, the safe concentration was 0.159 ml/L. The results on the effects of micronucleus （MN） in erythrocytes of Danio redo induced by bensulfuron-methyl at different times and different concentrations showed that the MN rate of control group was 0.010 3%, the highest MN rate of experimental group reached to 0. 372%, it also indicated that bensulfuron-methyl herbicide had genetics toxicity to Danio redo. At the same detection time, there was dose-effect relationship of MN rate in erythrocytes between treatment and control groups with different concentrations. In the same treatment group, the MN rate in erythrocytes reached to peak value at 24 h, and decreased at 48 h and 72 h with the infection time was prolonged. [ Conclusion ] The study provides some basis for scientifically selecting and reasonably using herbicide.
