Abstract: The transplants of one-year-old Glycyrrhiza uralensis Fisch. were subjected to five concentrations of MnSO₄·H₂O (0, 1.81, 18.1, 36.2 and 54.3 mg·L^-1) culturing in vermiculite. qRT-PCR and HPLC were respectively used to measure the relative expression of SQS1 gene and the content of glycyrrhizic acid of G.uralensis in different concentrations of MnSO₄·H₂O. This is to explore discuss the effects of the expression of SQS1 gene and the accumulation of glycyrrhizic acid by Mn treatment. The results showed both the expression of SQS1 gene and the content of glycyrrhzic acid of G. uralensis tended to rise after the fall of the first with the increase of concentration of Mn treatment. And they were of very significant positive correlation (P < 0.01, r=0.737). Relative expression of SQS1 gene reached the highest 7.90 under 18.1 mg·L^-1 MnSO₄·H₂O treatment. It was very significantly different between 18.1 mg·L^-1 concentration of MnSO₄·H₂O treatment and CK (0 mg·L^-1), 1.81, 36.2 and 54.3 mg·L^-1 (P < 0.01), and 1.75, 1.37, 1.37, 2.33 times respectively. The content of glycyrrhizic acid reached the highest under 1.81 and 18.1 mg·L^-1 MnSO₄·H₂O treatment, and there were not significant difference (P > 0.05). It was very significantly different between them and other concentrations of MnSO₄·H₂O treatment (P < 0.01). This study suggests the appropriate concentration of Mn treatment could certain promote the expression of SQS1 gene and the accumulation of glycyrrhizic acid of G. uralensis.