Abstract: S-adenosylmethionine(SAM)plays important roles in trans-methyl reactions.Under drought(30%PEG),salinity(200 mmol/L NaCl) and low temperature(4℃),total RNA was extracted from the leaf of Glycine soja and the first strand of cDNA was synthesized with reverse transcription.S-adenosylmethionine synthetase gene(SAMS gene) was amplified by PCR with the first strand cDNA as template and a pair of primers which was based on constructed ESTs sequence.Full-length SAMS gene sequence was obtained by BLAST comparison.According to the analysis,completed sequences of SAMS gene was integrality.The sequence of the SAMS gene is 1185 bp in length with an opening reading frame(ORF) encoding 394 amino acids.The cDNA sequence shows a significant homology to the SAMS genes from Phaseolus lunatus(89%),Medicago sativa(85%).There was a prokaryotic expression vectors based on pET-32b had been constructed and prokaryotic expression analyzed;To lay a strong foundation for resist adversity function analysis through situation of genic expression analysis.