Based on the reported cDNA sequences of BmKαTxs , the genes encoding toxin BmKαTx11 and BmKαTx15 were amplified by PCR from the Chinese scorpion Buthus martensii Karsch genomic DNA employing synthetic oligonucleotides. Sequences analysis of nucleotide showed that an intron about 500 bp length interrupts signal peptide coding regions of BmKαTx11 and BmKαTx15. Using cDNA sequence of BmKαTx11 as probe, southern hybridization of BmK genome total DNA was performed. The result indicates that BmKαTx11 is multicopy genes or belongs to multiple gene family with high homology genes. The similarity of BmKα-toxin gene sequences and southern hybridization revealed the evolution trace of BmKα-toxins: BmKα-toxin genes evolve from a common progenitor, and the genes diversity is associated with a process of locus duplication and gene divergence.