Abstract: The venom from the East-Asia scorpion (Buthus marttensii Karsch) was isolated and purified by Sephadex G-50 and sp-Sephadex G-25 chromatography one after another.Different mammal neurotoxins BmK Ⅰ-Ⅷ and crustacea neurotoxin were obtained.The results of electrophoresis and isoelectric focusing on polyacrylamide gel showed that they are homogencous on the whole.Except the Bmk Ⅳ,their isoelectric points are range from 7.9 to 9.1.The Pi of BmK Ⅳ is pH 5.3.The molecular weights determined by SDS PAGE are range between 6000 and 8000.The amino acid compositions showed that BmK Ⅰ-Ⅷ have a higher content of Asp and 1/2 Cys and lack Met but CT has a higher content of Gly and lacks Ile and Val. The comparison of N-terminal partial scquences of 15 amino acid residuces between BmK Ⅳ and BmK Ⅲ showed the homology more than 60%.The far UV CD Spectrum of several neurotoxins indicate that a mixture of β-pleatad sheet and aperiodic structure is the main feature of the secondary structure of them.