Abstract： Objective To obtain the cDNA and sequence analysis of α-neurotoxin (α-NT) from Guangxi king cobra (Ophiophagus hannah，Oh)．Methods　Comparative analysis of the determined cDNA sequences of α-NT from elapidae snake venoms showed that the nucleotide sequences of 5'，3'-non-coding regions and the signal peptide coding region were highly conserved．Thus the sense primer was designed from 5' conserved regions， which contain the start codon ATG． The antisense primer d (T) was used for amplification of cDNA 3end (RACE-PCR)．Two primers were designed from the 5'， 3'- coding regions for overcome the mistake amplification by the primer．4 couple primers of P1， P2， P3 and P4 were designed from those 4 primers．Venom gland RNA was extracted from three snakes of Oh with isolation kit． The extracted RNA was then reverse transcribed into cDNA with oligo (dT) antisense primer． After RT-PCR with the designed primers the 4 fragments of PCR product isolation with electrophoresis were achieved． The nucleotides sequence analysis of fragment was on the ABI PRISM 310 automatic DNA sequencer．Results　The nucleotide sequence of 474 base pairs consisting of a 5'-untranslated region (6bp)， signal peptide with ATG (63 bp)， protein coding region (216 bp) and 3'-untranslated region (186 bp) with a TGA termination codon． Comparison of the cDNA of long chainα-NT between Oh snake and other snakes found the nucleotide sequence much higher corresponding to the signal peptide than the mature protein coding regions which is about 100% identical to Pseudonnaja textiles(Pt) and Laticauda semifasciata(Ls)，96.8% to Naja sputatrix(Ns) and Bungarus multicinctus(Bm)．Encoding 93 amino acid residues containing a signal peptide (21 amino acid residues) and Oh-toxin (72 amino acid residues) with 10 cysteine residues could be determined．The conservation of mature protein region about 83.3% to Ns，79.2% to Pt，76.4% to Ls and 74.1% to Bm snakes．It was found that the among conservation of Oh-toxin from cDNA，90.3% was identical to Oh Toxin a， about 73.6% to Oh Toxin b， 69.4% to Oh-4，66.7% to Oh-5， 56.9% to Oh-6A and Oh-6B；and 65.3% identical to LNTX， 61.1% to toxin a and 54.2% to α-bungarotoxin．Conclusion The result indicates that newly found Oh cDNA is a long chain α-NT gene．