Dihydroflavonol 4-redudase (DFR) is part of an important step in the flavonoid biosynthesis pathway of anthocyan ins. We isolated the DFR gene from Brassica rapa ssp. pekinesis (Chinese cabbage), and found that biosynthesis of anthocyanins in tobacco could be modulated by introducing a heterologous $DFR_{Bra}$ gene. RT-PCR showed that transgenic plants had abnormal flower colors compared with the wild-type controls, a response that was correlated with the level of DFRBra transcription. HPLC analysis revealed that the isolated $DFR_{Bra}$ cDNA mainly produced cyanidin as well as a small amount of pelargonidin in the anthocyanin biosynthesis pathway of those tobacco plants.