Abstract: Geranylgeranyl pyrophosphate synthase(GGPPS) is an important target site for regulating diterpenoid biosynthesis in plant cells. Now,a novel geranylgeranyl pyrophosphate synthase gene (SmGGPPS3) was cloned from the medicinal plant Salvia miltiorrhiza. The full-length SmGGPPS3 consists of 2908 nucleotides,including a 931-bp intron and one 960-bp ORF encoding region. The deduced protein of SmGGPPS3 showed more than 67% similarity with GGPPSs from Ricinus communis,rubber and Arabidopsis.Quantitative RT-PCR analysis revealed that SmGGPPS3 was significantly expressed in different development stages and different tissues examined,and could be induced by methyl jasmonate(MeJA) and pathogens.Furthermore,the genetic complementation expression of SmGGPPS3 in Escherichia coli revealed that SmGGPPS3 encoded a functional GGPP synthase.