Objective To investigate the effects of Huopo Xialing Decoction combined with western medicine on lipid metabolism, pancreatic islet function, and visceral fat in patients with obese type 2 diabetes mellitus (T2DM). Methods A total of 300 patients with obese T2DM treated in Shaoxing Shangyu District Hospital of Traditional Chinese Medicine from January 2025 to January 2026 were enrolled and divided into an observation group and a control group by random number table method, with 150 cases in each group. The control group received metformin combined with dapagliflozin orally, while the observation group was additionally administered Huopo Xialing Decoction with high performance liquid chromatography (HPLC) fingerprint-based quality control. The treatment course lasted 12 weeks. Lipid metabolism indicators[total cholesterol (TC), triacylglycerol (TG), low density lipoproteincholesterol (LDL-C), high density lipoprotein-cholesterol (HDL-C)], pancreatic islet function[fasting blood glucose (FBG), fasting insulin (FINS), homeostasis model assessment of insulin resistance index (HOMA-IR), HOMA-β], visceral fat area (VFA), and clinical efficacy were compared between the two groups. Results After treatment, the levels of TC, TG, LDL-C, FINS, and HOMA-IR in the observation group were all lower than those in the control group(all P＜0.05), while the levels of HDL-C and HOMA-β were higher than those of the control group (all P＜0.05). VFA in the observation group was smaller than that in the control group (P＜0.05). The HbA1c＜ 7.0% attainment rate and the proportion of patients with HbA1c reduction≥1.0% in the observation group were superior to those in the control group (all P＜0.01), and the comprehensive clinical effective rate was higher than that of the control group (P＜0.01). Conclusion Huopo Xialing Decoction combined with western medicine can effectively ameliorate lipid metabolism disorders, alleviate insulin resistance, reduce visceral fat accumulation, and improve the glycemic control target rate in patients with obese T2DM, with superior comprehensive efficacy compared with western medicine alone and a favorable safety profile.