To investigate the effects of Dapagliflozin on insulin secretory function and serum adipokine expression levels in patients with primary diagnosis of type 2 diabetes mellitus (T2DM). 82 T2DM patients initially diagnosed in our hospital from January 2021 to April 2022 were recruited, and 64 patients who were successfully screened were randomly divided into two groups: 32 patients entered the Metformin group (with a dose of 0.5–1.0g, twice a day, for 12 weeks), and 32 patients entered the Dapagliflozin group (with a dose of 10 mg, once a day, for 12 weeks). General clinical data and laboratory test index levels were collected and analyzed before and after medication in 2 groups of patients: ①waist circumference, waist-hip ratio, body mass index (BMI); ②lipid metabolism indexes: high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C); ③insulin secretory function indexes: fasting plasma glucose (FPG), 2-h postprandial glucose (2hPG), fasting C-peptide (FC–P), 2-h postprandial C-peptide (2 hC-P), fasting insulin (FINS), 2-h postprandial insulin (2hINS); ④homeostasis model assessment indexes: homeostasis model assessment β cell (HOMA-β), homeostasis model assessment insulin resistance index (HOMA-IR); ⑤serum adipokines: adiponectin, retinol binding protein 4 (RBP4), interleukin-6 (IL-6), tumor necrosis factor α (TNF-α). The differences in the values of the baseline data and the levels of laboratory tests indicators were not statistically significant between the 2 groups of patients before dosing (P > 0.05). After dosing, ①waist circumference, waist-hip ratio and BMI decreased in the Dapagliflozin group, and waist circumference in the Dapagliflozin group was smaller than that in the Metformin group (P < 0.05); ②HDL-C levels increased and LDL-C levels decreased in both groups, and HDL-C levels were higher and LDL-C levels were lower in the Dapagliflozin group than in the Metformin group (P < 0.05); ③FPG and 2hPG levels decreased and 2 hC-P, FINS and 2hINS levels increased in both groups, and FPG and 2hPG levels were higher in the Dapagliflozin group than in the Metformin group, FC-P, 2 hC-P, FINS and 2hINS levels were lower in the Dapagliflozin group than in the Metformin group, and FC-P level in the Dapagliflozin group were higher than before dosing (P < 0.05); ④HOMA-β increased and HOMA-IR decreased in both groups, and HOMA-β was higher and HOMA-IR was lower in the Dapagliflozin group than in the Metformin group (P < 0.05); ⑤the expression levels of adiponectin increased and RBP4, IL-6 and TNF-α decreased in both groups, and the expression levels of adiponectin was higher and RBP4, IL-6 and TNF-α were lower in the Dapagliflozin group than in the Metformin group (P < 0.05). Dapagliflozin was superior to Metformin in improving morphology, modulating insulin secretory function and serum adipokine expression levels in the treatment of patients with primary diagnosis of T2DM.