Abstract: In order to assess the developmental toxicity and genotoxicity of acetochlor on the early development of Xenopus tropicalis,the teratogenicity on embryos exposed to acetochlor was investigated by modified frog embryo teratogenesis assay-Xenopus(FETAX).The teratogenic median concentration (TC50) value of acetochlor was 1.20 mg (a.i)/L.Acetochlor could induce a variety of malformations on X.tropicalis embryos,such as facial abnormality,pericardial edema,notochord and tail flexures,cephalic dysplasia and gut malformation.The calculated teratogenic index (TI) value was 1.88,suggesting that acetochlor had a teratogenic potential.Furthermore,the DNA damage was observed on the erythrocytes of tadpoles 4 days after exposed to sub-lethal concentrations of acetochlor by micronucleus test and alkaline single-cell gel electrophoresis.Compared to the control group,the results showed that the micronucleus frequencies were increased significantly,and the tail DNA and Olive tail moment of Comet picture had significant difference after treatment of acetochlor,which indicated that the DNA of erythrocytes was damaged.