Ethnopharmacological relevance: Millettia speciosa Champ., also called Niu dali, is a fabaceous medicinal plant mainly distributed in southeast China, where it is a functional food for developing physical strength, and often used traditionally in medicinal treatment of numbness of the wrists, diabetes, hepatitis, and so on. Aim of the study: To investigate the chemical profile, ameliorating effects of MSC on glycolipid metabolism in diabetic mice and to identify the possible mechanism of action. Materials and methods: High-performance liquid chromatography coupled with electrospray ionization quadrupole time of flight mass spectrometry (HPLC-ESI-QTOF-MS) was applied to analyze the chemical compositions from M. speciosa extract (MSC). MSC was orally administered to high-fat diet and STZ-induced diabetic mice at doses of 4.55, 9.10 and 13.65 mg/(kg·d) respectively for 10 weeks. Indices of glycolipid metabolism, including fasting blood glucose (FBG), fasting insulin, insulin resistance index (IRI), blood lipids, HPA-axis hormones, and related gene expressions were evaluated. Results: 86 compounds were tentatively identified from MSC, counting for 91.97% of the total extract, mainly including 23 alkaloids (including 2 cyanogenetic glycosides firstly identified in this species, total content accounted to 39.71%), 23 flavonoids (11.91%), 17 acids (including 3 amino acids, 9 phenolic acids and 5 organic acids; 9.2%), 9 terpenoids and steroids (20.13%), 7 esters (3.33%), 3 lignans (3.73%), 3 saccharides (4.0%) and 1 anthraquinone (0.18%). MSC could ameliorate the glycolipid disorder in diabetic mice markedly, and significant regulations on CRH and ACTH hormones were observed. Moreover, the cellular morphology of liver and pancreas were significantly improved and the expressions of IRS2, PI3K, Akt and GLUT4 were significantly up-regulated by MSC treatment. Conclusion: This was the first time to study the chemical profile and ameliorating effect on glycolipid metabolism of M. speciosa. It was found to be rich in flavonoids and alkaloids, which might support the potential relation of material foundation and the activity in regulating glycolipid metabolism. The ameliorating effect on glycolipid disorder in diabetic mice might be associated to the regulation of related hormones of the HPA axis and the IRS2/PI3K/Akt/GLUT4 signalling pathway. It was of great significance for advanced directed separation and pharmacological activity research of MSC. © 2021