The saponins of had many pharmacological activities such as antitumor, antioxidation, and blood sugar lowering, which were synthesized by two pathways: mevalonate (MVA) and methylerythritol phosphate (MEP). 3-Hydroxy-3-methylglutaryl coenzyme A synthase (HMGS) was the key enzyme in the MVA synthesis pathway, and its expression level may affect the accumulation of saponins which were the main active ingredients of . In this study, we successfully cloned and from and their sequence similarity was 93.71% with 89 different sites. The multiple sequence alignment results indicated that the N-terminal sequences of HMGS were conserved. Phylogenetic analysis showed that , , , , and other relatives had a common evolutionary ancestor. The expression levels of both and the total saponin content in different tissues revealed that expression in rhizomes was positively correlated with total saponin content. Further study of the abiotic stress effect of Methyl Jasmonate (MeJA) demonstrated that the expression of and genes was induced by MeJA, peaked at 24 h, and fell by 48 h. Our present findings would provide a blueprint for future studies of and its role in triterpenoid biosynthesis in .