AIM:To discuss the effect of Shenmai injection on insulin resistance ( IR) in 3T3-L1 cells and its mechanisms.METHODS:3T3-L1 preadipocytes were induced by chemical reagents to differentiate into fully differentiated adipocytes.Oil red O staining was used to detect the differentiation level of the adipocytes .The insulin-resistant 3T3-L1 cell model was demonstrated using insulin , which was confirmed by glucose concentration in cell supernatant .The IR cell model was given 10 μmol/L rosiglitazone , 25 and 50 g/L Shenmai injection and normal saline for comparison .MTT assay was used to assess the cell activity of 3T3-L1 cells which was treated with drugs for 8, 16, 24 and 36 h.Glucose oxidase method was used to detect the glucose concentration in the cell supernatant at 8, 16 and 24 h.The protein levels of glucose transporter-4 (GLUT4), phosphatidylinositol 3-kinase (PI3K), AKT and p-AKT were determined by Western blot .RE-SULTS:3T3-L1 adipocytes were successfully induced as shown by the positive oil red O staining .The IR cell model was demonstrated , and glucose concentration in the cell supernatant after treatment with Shenmai injection showed that Shenmai injection reduced the IR in 3T3-L1 cell model.The protein levels of GLUT4, PI3K and p-AKT increased compared to con-trol group.CONCLUSION:Shenmai injection reduces the IR in 3T3-L1 cell model, which functions by increasing the protein levels of GLUT4, PI3K and p-AKT.