As transient expression systems are effective methods for the functional characterization of genes, a transient gene expression and silencing system was developed for Betula platyphylla Suk (Chinese Birch).Firstly, the cinnamoyl-CoA reductase (CCR) gene and its promoter were isolated from Chinese Birch.The vectors for overexpression of CCR and RNAi-based silence of CCR were constructed and transformed into Agrobacterium, respectively.Overexpression and silence of the CCR gene were respectively performed on Birch seedlings using an Agrobacterium-mediated transient expression system.The expression levels of CCR were determined by using real-time PCR.The results showed that the transcripts of CCR notably increased in the Birch plants transformed with the CCR overexpression construct, and notably decreased in plants transformed with the silencing construct when compared with nontransgenic plants.These studies confirmed that this transient genetic transformation system works well on Birch plants, and can be used for the functional characterization of genes and protein production in Birch.