Abstract: To determine the effect of aging process on the toxicity of exogenous Sb(III) in soil, combining with chemical analysis and toxicity test, the changes of oxidation state, extracted concentration of exogenous Sb(III) and its growth, fertility, and reproduction toxicity on model organism Caenorhabditis elegans after 7 and 56 d aging in Anhui yellow-brown soil and Xinjiang grey dessert soil. The proportion of Sb(V) in Anhui yellow-brown soil and Xinjiang grey desert soil aged for 56 d were significantly higher than that aged for 7 d. Sb(III) in Xinjiang grey desert soil can be oxidized to Sb(V) faster than that in Anhui yellow-brown soil. Compared with 7 d aging, the ratio of extracted Sb in Anhui yellow-brown soil and Xinjiang grey desert soil with 56 d aging decreased by 27.0% and 32.5%; respectively; the EC₅₀ (50% effect concentration) of exogenous Sb(III) on the growth toxicity of C. elegans increased by 1.7 and 2.3 times, respectively; the EC₅₀ of exogenous Sb(III) on the fertility toxicity of C. elegans increased by 1.1 and 2.4 times, respectively; the EC₅₀ of exogenous Sb(III) on the reproduction toxicity of C. elegans increased by 1.2 and 1.9 times, respectively. The aging factor of exogenous Sb (III) in Xinjiang grey desert soil calculated based on EC₅₀ value were higher than that in Anhui yellow-brown soil, which was consistent with the higher oxidation efficiency of Sb(III) and the decline proportion of extracted Sb in Xinjiang grey desert soil. pH, organic matter and iron, manganese, aluminum oxide could explain the difference of exogenous Sb(III) oxidation efficiency and extracted Sb concentration between Anhui yellow-brown soil and Xinjiang grey desert soil.