Abstract: Abstract: Alpha-bungarotoxin is one of the post-synaptic neurotoxins, which widely exists in the Elapidae venom. The polymorphism of α-bungarotoxin’s cDNA sequences has been controversial in previous reports. In the present study, cloning of α-bungarotoxin gene from the genomic DNA, sequencing of five clones and analysis of their polymorphism were reported. Furthermore, we cloned and sequenced the nerve growth factor (NGF) gene from the same cDNA pool as a standard, and compared the mutation rates among different sources of α-bungarotoxin cDNAs, α-bungarotoxin genes and NGF cDNA. The results indicated that there was no diversification in the genome or comparability in the mutative points between different cDNA sequences. Therefore, we speculate that the polymorphism of α-bungarotoxin cDNA resulted neither from different transcripts, nor from RNA editing, but possibly from reverse transcript processes and gene-cloning processes.