Erigeron breviscapus is a medicinal plant with the most developmental potential in Yunnan province, which is belongs to Erigeron genus of Compositae family. Scutellarin, the main active component of Erigeron breviscapus is one of flavone 7-O-glucuronide derivatives, its biosynthesis pathway is still not clear.Full length cDNA encoding flavone syhthase II gene in E. breviscapus was cloned in this study using R-PCR, 3'-RACE and 5'-RACE.The opening reading frame of FS II cDNA of E. breviscapus is 1 557 bp long and encoding 518 amino acids, designed as EbFS II, which is highly homologous with FS II of Compositae species, like Callistephus chinensis, Cynara cardunculus var. scolymus, Gerbera hybrida, Dahlia pinnata and Lobelia erinus.Phylogenetic analysis showed that EbFS II might has the function of directly converting flavanone to flavone.