Abstract: (3S)-Linalool synthase (LIS) is a key enzyme involved in the monoterpene biosynthetic pathway. Based on our previous transcriptome study, the expression level of LIS gene was exceedingly related to glycyrrhizic acid (GA) biosynthesis. Therefore, we used hairy root culturing to further investigate the effect of LIS on the GA biosynthesis. A LIS gene (GenBank accession number: MZ169552) was cloned from Glycyrrhiza uralensis. The plant binary overexpression vector pCA-LIS was constructed by gene fusion. G. uralensis hairy roots overexpressing LIS were induced by the Agrobacterium rhizogenes ATCC15834. The expression levels of LIS were analyzed by real-time quantitative PCR (RT-qPCR) and the contents of GA in hairy root lines were determined by UPLC. It was found that in the hairy root lines overexpressing LIS, the expression levels of LIS were significantly higher than that in the wild type, while the contents of GA were remarkably lower than those in the wild type and negative control. These findings indicate that the expression level of LIS is negatively correlated with the accumulation of GA. In this study, LIS was cloned from G. uralensis for the first time and the negative regulatory effect of LIS on GA biosynthesis was confirmed by reverse genetics. This work provides support for further improvement of the molecular regulatory network of GA biosynthesis in G. uralensis.