Objective: To investigate the correlation between visceral fat/subcutaneous fat ratio and islet β cell function in overweight/obese patients. Methods: A total of 96 overweight/obese patients with body mass index (BMI) >24 kg/m² treated in Putuo Hospital Affiliated to Shanghai University of Traditional Chinese Medicine from June 2020 to January 2022 were included in the study. Visceral fat area (VFA), subcutaneous fat area (SFA), height and weight were measured and BMI was calculated. Fasting blood glucose (FBG), glycosylated hemoglobin (HbA1c), fasting insulin (FINS), postprandial insulin, fasting C-peptide, postprandial C-peptide were determined. Lipid factors such as fibroblast growth factor 21 (FGF-21), leptin (LEP), adiponectin (ADP), and gastrointestinal hormones such as glucagon-like peptide-1 (GLP-1) and recombinant peptide YY (peptide YY) were determined. The visceral fat/subcutaneous fat ratio, homeostasis model insulin resistance index (HOMA-IR), and islet β cell function index (HOMA-β) were calculated. According to visceral fat/subcutaneous fat ratio, patients were divided into a low visceral fat/subcutaneous fat ratio group and a high visceral fat/subcutaneous fat ratio group, and the correlation between VFA/SFA and islet β cell function and adipokine was analyzed. Results: VFA, FBG, HbA1c, and YY peptides in the low VFA/SFA group were lower than those in the high visceral fat/subcutaneous fat ratio group, while SFA, postprandial C peptide, HOMA-β, FGF-21, and LEP were higher than those in the high visceral fat/subcutaneous fat ratio group, and the differences between the 2 groups were statistically significant (all P<0.05). The VFA/SFA was positively correlated with FBG and HbA1c (r values were 0.344 and 0.434, respectively, P<0.05), and negatively correlated with postpranpranal C-peptide, HOMA-β, FGF-21, and LEP (r values were −0.406, −0.343, −0.345, −0.344, respectively, P<0.05). Conclusion: The higher the visceral fat/subcutaneous fat ratio, the higher the levels of FBG and HbA1c, and the lower the postprandial C-peptide, HOMA-β, FGF-21 and LEP. Different from the traditional visceral fat content, the visceral fat/subcutaneous fat ratio also considers the effect of subcutaneous fat content on islet β cell function, and comprehensive analysis of fat distribution, which is helpful to comprehensively evaluate the severity of islet function injury and glucose metabolism in overweight and obese patients.