Abstract: Abstract: 【Objective】In this study, we explored the biological functions of the MYB gene in triterpenoid metabolism and examine MYB expression patterns induced by MeJA and SA treatment and expression specificity in different birch(Betula platyphylla Suk.)tissues.【Method】A new MYB transcription factor gene from birch was obtained by RT-PCR, and its protein characteristics and phylogenetic relationships were analyzed using bioinformatics methods. The expression pattern induced by MeJA and SA treatment was determined using real-time fluorescence quantitative PCR.【Result】A new gene of the MYB family transcription factor, named BpMYB21, was cloned from birch. The gene contains a complete 1 014 bp open reading frame(ORF), encoding a 337 amino acid protein. The BpMYB21 protein has an amino acid homology of 51%-64% with other plants and is most closely related to the walnut(Juglans regia)MYB30-Like protein. BpMYB21 was expressed in the roots, stems and leaves of birch and the expression level in the leaves was higher than those in the stems and roots; however, the difference was not significant. In birch culture plants treated with 100 μmol/L MeJA and 50 mg/L SA for 6 h, the expression of BpMYB21 was the highest in the stems and leaves and expression levels gradually decreased with time from 12 to 48 h. 【Conclusion】 BpMYB21 is a new member of the MYB transcription factor family, which is closely related to walnut(Juglans regia). This gene is responsive to hormone induction and may play an important role in the growth and development and secondary metabolism of birch.