Abstract: The medium lethal concentration (LC₅₀) and the safe concentration (SC) of three heavy metals (Cr⁶⁺,Zn²⁺ andCd²⁺) to "All Male No.1" seed of Pelteobaqrus fulvidraco were tested at(28.0±1.5)℃,pH6.5~7.0.The results showed that the LC₅₀ of 24 h,48 h,72 h and 96 h forCr⁶⁺ to "All Male No.1" seed of P.fulvidraco were 168.71,84.85,52.23 and 34.46 mg·L^-1,respectively;the LC₅₀ of 24 h,48 h,72 h and 96 h forZn²⁺ to "All Male No.1" seed of P.fulvidraco were 5.36,3.34,3.12 and 2.75 mg·L^-1,respectively;the LC₅₀ of 24 h,48 h,72 h and 96 h forCd²⁺ to "All Male No.1" seed of P.fulvidraco were 1.87,1.74,1.63 and 1.15 mg·L^-1,respectively.The safe concentration ofCr⁶⁺,Zn²⁺ andCd²⁺ to "All Male No.1" seed of P.fulvidraco were 3.446,0.275 and 0.012 mg·L^-1,respectively.Taken together,to "All Male No.1" seed of P.fulvidraco,the toxicity of three heavy metal ions was in the order ofCd²⁺ >Zn²⁺ >Cr⁶⁺,whileZn²⁺ andCd²⁺ had medium toxicity,andCr⁶⁺ had low toxicity.