Amorpha-4,11-diene synthase (ADS) can convert farnesyl pyrophosphate (FPP) to amorpha-4, 11-diene, a precursor of artemisinin.  ADS plays an important role in the biosynthesis of artemisinin.  This  review summarizes the molecular biology and metabolic engineering study of ADS in recent years.  The    genomic DNA and its cDNA sequences of amorpha-4, 11-diene synthase were cloned from Artemisia annua L.  The cDNA encoding amorpha-4, 11-diene synthase contains a 1 641 bp open reading frame coding for 546 amino acids.  ADS shows a broad pH optimum and an absolute requirement for divalent metal ions as cofactors.  The specificity of ADS to the substrates and products is not high and the formation of amorpha-4, 11-diene by   ADS from FPP is achieved by an initial 1, 6-closure with subsequent 1, 10-closure.  The ADS cDNA cloned from Artemisia annua L, or totally synthesized by PCR, was introduced into different hosts including E. coli,   S. cerevisiae, Nicotiana tabacum L. Arabidopsis thaliana and A. nidulans resulting in varied engineering     microorganisms and cells producing amorpha-4, 11-diene.  The way to improve the production of amorpha-   4, 11-diene was investigated by two strategies such as improving the supply of substrate and directing FPP flux to amorpha-4, 11-diene production from competing pathways.