To research the correlation between the accumulation of iridoids and expression of key enzymes genes of Gentiana macrophylla,UPLC-Q-Exactive MS was used to detect iridoids content,and then quantitative real-time PCR (qRT-PCR) was used to analyze the expression of key enzyme genes in iridoids biosynthesis.Correlation was calculated by SPSS.The results showed that most iridoids were mainly distributed in roots,while loganic acid 11-O-β-glucopyranosyl ester was distributed in leaves and secologanoside was distributed in flowers.The expression of genes was higher in flower parts than in other parts,the expression of loganate O-methyltransferase(LAMT) was the highest in leaves and the expression of genraniol 8-hydroxylase (G8O) was the highest in roots.Correlation analysis showed that the relative expression of 7-deoxyloganetic acid glucosyltransferase (7-DLGT), isopentenyl-diphosphate delta-isomerase (IDI),secologanin synthase (SLS),mevalonate pyrophosphate decarboxylase (MVD) and 7-deoxyloganic acid 7-hydroxylase (7-DLH) genes were positively correlated with the contents of iridoids.The expression of the key enzyme genes play an important role in the synthesis of iridoids,which lay a foundation for the regulation of the accumulation of iridoids,and is also an important part of the mechanism of quality formation in the G. macrophylla.