Tanshinones, the main bioactive compounds of Salvia miltiorrhiza, are the diterpenoid pigments, multiple genes were proved to be involved in their biosynthesis in plants. CYP76AH1 is the initial P450 gene in the tanshinones biosynthetic pathway, its function has been validated by yeast expression and in vitroenzymatic reaction. In order to clarify the function of CYP76AH1 in vivo, in this study, we constructedthe RNA interference of CYP7AH1 in S. miltiorrhiza hairy root. The RNA interference vector with a hairpin structure was constructed using the Gateway technology, and then the interference fragment was integrated into the genome of S. miltiorrhiza mediated by Agrobacterium rhizogenes. Several highly CYP76AH1 interference S. miltiorrhiza hairy roots were obtained for further analysis.