Abstract: Abstract : In recent years, antimony (Sb), a new pollutant, has attracted much attention, but the ecological toxicity of Sb in soil remains to be studied.The effects of Sb⁵⁺ on the survival, antimony enrichment, total protein, antioxidant system enzymes and malondialdehyde of e. fetida, a model invertebrate organism, were investigated by adding potassium pyoantimonate (KSbO₆H₆) to artificial soil to simulate contaminated soil. The toxicity of earthworms under antimony stress was evaluated by biomarker response index (BRI).The results showed that the mortality rate of earthworms increased with the increase of Sb concentration and exposure time, and the dose-effect relationship was obvious. The LC₅₀ of earthworms in 56 days was 3227 mg/kg. Only a small amount of Sb⁵⁺ was absorbed by earthworms, and the highest treatment group was only 213.34mg/kg after 56 days of exposure. Superoxide dismutase (SOD), Peroxidase (POD) and Malondialdehyde (MDA) increased first and then decreased within 28 days of exposure. Catalase（CAT) showed a trend of "up-down-up-down-down", and total protein showed a trend of continuous decline with the increase of time and treatment level. The lowest BRI value was 2, and only four treatment groups had BRI less than 2.5 at 21 and 28 days of exposure, considered as a serious health effect. In general, Sb⁵⁺ had low ecotoxicity to E. fetida.