Abstract: The full length cDNA sequence of Deoxyoxylulose-5-phosphate synthase gene（JsDXS）was cloned from Jasminum sambacby using RT-PCR and rapid amplification of cDNA ends（RACE）method. According to the 2 505 bp sequence，the promoter of JsDXS was isolated using Genome Walking Method. The gene expression pattern in blooming was analyzed by the real-time PCR. Gene structure analysis showed that the full length cDNA contained a 2 145 bp open reading frame（ORF），encoding a protein of 714 amino acid. There were several conserved domains，such as TPP-DXS，TPP-PYR-DXS- TK-like，Transketolase C，etc. One 745 bp sequence was found to be the promoter of JsDXS，which contained many cis-acting elements，such as TATA-box，T/GBOXATPIN2（related to jasmonate signaling），MYCCONSENSUSAT（related to cold stress），CIACADIANLELHC（necessary for circadian expression）.The real-time PCR analysis revealed that the gene expression at 18：00 was low and started to increase and reached a maximum at 22：00，and then started to decrease and reached a minimum at 2：00. This phenomenon perhaps illustrated that the expression of JsDXS was regulated by circadian.

Key words: Jasminum sambac, aroma, deoxyoxylulose-5-phosphate synthase, promoter, cis-acting element, expression analysis