Abstract: Objective Subacute toxicity of abamectin was studied and the oxidative damage was reported. Methods A total of 30 healthy Wistar rats (15 male and 15 female) were randomly divided into 3 groups,such as 5.38 mg/kg(1/4 LD50),2.69 mg/kg (1/8 LD50) and control group(oil). The drug was given for 30 days by gavage. The rats were observed daily and weighted per week. At the end of experiment,the histopathological examinations of selected organs were done and the serum MDA,GSH-Px and SOD activity were measured. Results The treatment of abamectin significantly affected the body weight increment during experimental periods. There were statistical differences in the ratios of organs (brain, liver and kidney) to body weight among three groups of female rats(F=22.34、93.15、60.77,P < 0.05),and these ratios were significantly high in the treated female rats with 5.38 mg/kg. There were statistical differences in the serum MDA,GSH-Px and SOD activity among three groups (F=57.48、120.62、30.45, P < 0.05),and they were significantly decreased in the treated group. The histopathological examination showed that the liver in the treated rats had obvious damages. Conclusion Subacute oral exposure to abamectin at 5.38 mg/kg could cause obvious toxicity,the liver might be sensitive organ and oxidative damage maybe play important role.