Objective: To analyze the influence of vitamin D combined with novorapid on Visfatin and pregnancy outcomes in patients with gestational diabetes mellitus (GDM). Methods: A total of 112 patients with GDM who were admitted to the hospital from June 2020 to December 2024 were selected and classified into single group (56 cases, novorapid) and combined group (56 cases, vitamin D on the basis of single group) by adopting random coin tossing method. After 4 weeks of continuous treatment, the levels of blood glucose and insulin indexes [fasting plasma glucose (FPG), 2h postprandial blood glucose (2hPG), serum fasting C-peptide (FCP), serum fasting insulin (FINS)], serum factors and blood lipids [serum tumor necrosis factor-α (TNF-α), Visfatin, low density lipoprotein cholesterol (LDL-C), total cholesterol (TC)] were compared between the two groups of patients with GDM before and after treatment, and the adverse pregnancy outcomes (neonatal outcomes, maternal outcomes) and natural delivery rate in the two groups were observed. Results: Compared with the same group before treatment, the levels of FPG, 2hPG, serum FINS and FCP in the two groups were lower after 4 weeks of treatment, and the levels in combined group were lower than those in single group (P<0.05). After 4 weeks of treatment, the levels of serum TNF-α, Visfatin, LDL-C and TC were lower in the two groups than those before treatment, and the levels were lower in combined group than those in single group (P<0.05). The incidence rates of preterm infant, neonatal hypoglycemia, polyhydramnios and pregnancy-induced hypertension were lower in combined group compared to single group (P<0.05), but no statistical differences were observed in the natural delivery rate and incidence rates of macrosomia, neonatal asphyxia, fetal distress and postpartum hemorrhage between the two groups (P>0.05). Conclusion: Combined therapy with vitamin D and novorapid for GDM patients can significantly control the blood glucose, improve the islet function, reduce the inflammatory factors and blood lipids, and lower the risk of adverse pregnancy outcomes.