In order to regulate the secondary metabolic pathway of a Chinese traditional medicinal material Fallopia multiflora by genetic engineering technology,a gene named FmPKS2（GenBank accession number： GQ984139） was cloned via the rapid amplification of complementary DNA end and bioinformatics analysis.The gene consists of 1498bp nucleotides for coding sequence,encodes 392 amino acids with a predicted relative molecular mass of 43160 and an isoelectric point of 5.85,and contains several highly hydrophobic regions with a hydrophobic coefficient of-0.154.Phylogenetic analysis reveals that FmPKS2 shares the closed relationship with chalcone synthase of polygonaceae family.The transcription of FmPKS2 can be found in all different tissues of Fallopia multiflora,with the highest quantity in rhizomes.