Plasma metabolomics combined experimental verification was employed for investigating of the hypoglycemic effect of Panax notoginseng saponins (PNS) on type 2 diabetes mellitus (T2DM) mice. Forty C57BL/6J mice were randomly divided into control and experimental groups after one week of adaptive feeding. The mice in control group were fed conventionally, and the T2DM model was established in mice of the experimental group by intraperitoneal injection of streptozotocin following twelve weeks of feeding on a high-fat diet (HFD). All experiments were approved by the Ethical Committee Experimental Animal Center of North Sichuan Medical College (NSMC2022023). After the failure cases during modeling were eliminated, the remaining mice were randomly divided into model group (T2DM), low dose [200 mg·kg^-1·d^-1] and high dose [300 mg·kg^-1·d^-1] PNS groups. Mice in normal and model groups were given equal amounts of normal saline by gavage. The mice were administered intragastrically with PNS for 6 weeks, and their body weight, food intake, water intake and fasting blood glucose (FBG) were measured weekly. Oral glucose tolerance test (OGTT) was performed at the 5th week of administration. The changes of liver functions and blood lipids were detected by collecting blood from eyeballs. Tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels were detected in the blood and the activity of glutathione peroxidase (GSH-Px), catalase (CAT) and superoxide dismutase (SOD) were analyzed in the liver by kit, respectively. Subsequently, the changes in plasma endogenous metabolites from each group were determined based on metabolomics, and the pathway enrichment analysis of differential metabolites was performed using KEGG database. NF-κB signaling pathway, TNF-α and IL-6 in liver were detected by western blot, respectively. The results showed that T2DM mice were successfully constructed. High dose of panax notoginseng saponins (HPNS) can reduce the FBG in T2DM mice while low dose of PNS (LPNS) has no significant effect on FBG. HPNS improves the liver function, reduces the levels of blood lipids, TNF-α and IL-6, and increases the activity of GSH-Px, CAT and SOD in liver of T2DM mice. Metabolomics results showed that 45 metabolites were significantly changed in the plasma of model group compared with control, and 20 metabolites were significantly changed after HPNS treatment. Pathway enrichment indicated that arachidonic acid metabolism, linoleic acid metabolism, glutathione metabolism and carnitine synthesis were changed in the blood of T2DM mice, and HPNS improved the abnormal metabolism of arachidonic acid and linoleic acid in T2DM mice. Western blot showed that HPNS could inhibit the NF-κB pathway and reduce the expression of TNF-α and IL-6 in the liver of T2DM mice, suggesting that PNS may exert the antidiabetic effect by inhibiting NF-κB pathway, regulating arachidonic acid and linoleic acid metabolism to reduce inflammatory factors and oxidative stress, improve liver function in T2DM mice.