In order to assess the effect of organosilicon surfactant as a novel adjuvant for agrochemical to aquatic organisms,the acute toxicity of four organosilicon surfactants SUSHENYIHAO,High-Speed,JIEXIAOLI and JIERUN were studied by semi-static method using zebrafish(Brachydanio rerio) as test organism.Safety evaluation has also been conducted.The results showed that the LC50 value of SUSHENYIHAO,High-Speed,JIEXIAOLI and JIERUN to zebrafish in 96 h were 135.0,17.4,11.3 and 5.9 a.i.mg/L,respectively.The acute toxicity of SUSHENYIHAO,High-Speed and JIEXIAOLI were low toxicity.The acute toxicity of JIERUN was middle toxicity.