Disorders of glucose and lipid metabolism are important causes of type 2 diabetes mellitus (T2DM). Defining the molecular mechanisms of metabolic disorders and exploring drug targets are key to the treatment of T2DM. The study discovered the effects of catalpol on insulin resistance (IR) and lipid metabolism disorder (LMD) in type 2 diabetes mellitus (T2DM). A T2DM mouse model was established by a high-fat diet and a single intraperitoneal injection of streptozotocin. and injected with catalpol at 10 mg/kg for 12 weeks, and the lentiviral vector of miR-101-3p or Fos-related antigen 2 (FOSL2) expression was interfered with intravenously mouse insulin resistance (IR) and lipid metabolism disorder (LMD)-related indices were then measured. Pancreatic histopathology was observed by hematoxylin and eosin (HE) staining and TUNEL staining. The miR-101-3p and FOSL2 were detected by RT-qPCR or Western blot. In results: catalpol improved IR and LMD (both P<0.05) in diabetic mice, and alleviated the histopathological changes in the pancreas. miR-101-3p was upregulated (P<0.05), and FOSL2 was downregulated (P<0.05) in T2DM mice, while catalpol rescued their expression pattern (both P<0.05). The miR-101-3p targeted FOSL2. Down-regulating miR-101-3p or up-regulating FOSL2 improved IR and LMD (all P<0.05) in diabetic mice, and alleviated pancreatic histopathological changes. Overexpressing miR-101-3p or suppressing FOSL2 weakened the ameliorative effects of catalpol in T2DM mice (all P<0.05). We conclude that catalpol improves IR and LMD in diabetic mice by inhibiting miR-101-3p to up-regulate FOSL2.