Based on the reported cDNA sequences of $BmK{alpha}Txs$, the genes encoding toxin $BmK{alpha}Tx11$ and $BmK{alpha}Tx15$ 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 $BmK{alpha}Tx11$ and $BmK{alpha}Tx15$. Using cDNA sequence of $BmK{alpha}Tx11$ as probe, southern hybridization of BmK genome total DNA was performed. The result indicates that $BmK{alpha}Tx11$ is multicopy genes or belongs to multiple gene family with high homology genes. The similarity of $BmK{alpha}$-toxin gene sequences and southern hybridization revealed the evolution trace of $BmK{alpha}$-toxins: $BmK{alpha}$-toxin genes evolve from a common progenitor, and the genes diversity is associated with a process of locus duplication and gene divergence.