Abstract：Objective：To investigate the mechanism of Yugan Prescription in treating insulin resistance （IR） in type 2 diabetes mellitus （T2DM） based on network pharmacology and animal experiments. Methods： Active components and target genes of Yugan Prescription were screened using the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform （TCMSP）. T2DM-related targets were collected from GeneCards and DisGeNET. Potential therapeutic targets of Yugan Prescription for T2DM were identified using the Venny 2.1 online platform. Core active components were screened with Cytoscape 3.9.1. Protein-protein interaction （PPI） network analysis was performed using the STRING database to identify core targets. Gene Ontology （GO） and Kyoto Encyclopedia of Genes and Genomes （KEGG） pathway enrichment analyses were conducted via the DAVID database. A T2DM mouse model was established using a high-fat， high-sucrose diet （HFD） combined with streptozotocin （STZ） injection. C57/6J mice were divided into six groups （n=10 per group）： the control group （Con）， the model group （Mod），the metformin group （Met），and the Yugan Prescription high- （YGF-H），medium- （YGF-M），and low- （YGF-L）dose groups. All groups received daily intragastric administration. The following parameters were measured： fasting blood glucose （FBG）， area under the curve （AUC） of oral glucose tolerance test （OGTT） and insulin tolerance test （ITT）， serum and tissue indices （liver， pancreas， white adipose tissue， spleen）， fasting insulin （FINS） ， homeostasis model assessment of insulin resistance （HOMA-IR） and insulin sensitivity index （HOMA-ISI），triglyceride （TG），total cholesterol （TC），low-density lipoprotein cholesterol （LDL-C），and protein expression levels of fibroblast growth factor 21 （FGF21） ， phosphatidylinositol 3-kinase （PI3K） ， phosphorylated PI3K （p-PI3K），protein kinase B （AKT），and phosphorylated AKT （p-AKT）. Pathological changes in liver and adipose tissues were observed by hematoxylin-eosin （HE） staining. Results：Fifty-six active components， 660 action targets， and 1 308 disease-related targets were identified， with 247 potential therapeutic targets. Core active components included phyllanthin， kaempferol， and toralactone. Core targets involved AKT1， PI3KCD， PI3KCB， and PI3KCA. The KEGG enrichment analysis highlighted pathways in cancer and the PI3K/AKT signaling pathway. After 1-6 weeks of treatment，FBG was significantly higher in the Mod group compared to the Con group （P＜ 0.05）； compared to the Mod group， FBG decreased in the Met and YGF-H groups （P＜0.05）. At 1-2 weeks and 4-6 weeks of administration， compared with the Mod group， the FBG of mice in the YGF-M group decreased （P＜ 0.05）. At 4-6 weeks of administration， compared with the Mod group， the FBG of mice in the YGF-L group decreased （P＜0.05）. Compared with the Con group， the levels of OGTT， ITT， FINS， and HOMA-IR in the Mod group were increased（ P＜0.05）；compared with the Mod group，the levels of OGTT，ITT，FINS，and HOMA-IR in the Met group and the Yugan Prescription groups were decreased （P＜0.05）；compared with the Met group，the levels of OGTT，FINS，and HOMA-IR in the Yugan Prescription groups were increased （P＜0.05），the level of ITT in the YGF-H group was decreased （P＜0.05），and the levels of ITT in the YGF-M and YGF-L groups were increased （P＜ 0.05）. Compared with the Con group，the level of HOMA-ISI in the Mod group was decreased （P＜0.05）；compared with the Mod group，the level of HOMA-ISI in the Met group and the Yugan Prescription groups was increased （P＜ 0.05）；compared with the Met group，the level of HOMA-ISI in the Yugan Prescription groups was decreased （P＜ 0.05）. Compared with the Con group，the levels of TG，TC，and LDL-C in the Mod group were increased （P＜0.05）. Compared with the Mod group，the levels of TG，TC，and LDL-C in the Met and YGF-H groups were decreased （P＜ 0.05）. Compared with the Con group， the indexes of liver， pancreas， spleen， and white adipose tissue in the Mod group were increased （P＜0.05）；compared with the Mod group，the index levels of the liver，pancreas，and spleen in the Met group and the Yugan Prescription groups were decreased （P＜0.05）. Compared with the Mod group， the pathological morphology of the liver and white adipose tissues in the Met，YGF-H，and YGF-M groups showed varying degrees of improvement. Compared with the Con group，the protein expression of FGF21，p-PI3K/PI3K，and p-AKT/ AKT in the liver tissue in the Mod group was decreased （P＜0.05）. Compared with the Mod group， the protein expression of FGF21，p-PI3K/PI3K，and p-AKT/AKT in the liver tissue of mice in the Met，YGF-H，and YGF-M groups was increased （P＜0.05）. Conclusion： Yugan Prescription can improve IR， glucolipid metabolism， and reduce liver，pancreas，and spleen indices in T2DM mice. The underlying mechanism may involve upregulating FGF21 expression and activating the PI3K/AKT signaling pathway，and improving IR in T2DM.