Phenylalanine ammonialyase was ratelimiting enzyme of phenylpropanoids components formation of Jasminum sambac. To understand the floral scent formation mechanism, we cloned the fulllength cDNA sequence of phenylalanine ammonialyase gene from J. sambac by RTPCR (reverse transcriptasepolymerase chain reaction) and RACE (rapid amplification of cDNA ends) methods (GenBank: KM406501.1). A 2 220 bp fulllength cDNA sequence was obtained and named JsPAL. The ORF (open reading frame) of JsPAL was 2 140 bp and encodes 712 amino acids, containing the conserved domain of lyase_I_like superfamily, active sites and tetramer interface (polypeptide binding site). The promoter of JsPAL was isolated by Genome Walking Method. A 1 201 bp sequence was found to be the promoter，which contains many important cisacting elements involved in flowering and floral scent formation, such as CCAATBOX1 (regulating flowering), elements of BOXLCOREDCPAL, PALBOXPPC, PALBOXLPC and TATABOXOSPAL (related to PAL gene), and MYBPLANT (involved in flowerspecific phenylpropanoid biosynthetic). The gene expression patterns in different stages of flower opening and different tissues were detected by the realtime PCR. The realtime PCR analysis revealed that the expression of JsPAL gene was high in flower buds and petals. Its expression was high before 22:00 and downregulated with the development of flower.