Objective Patients with newly diagnosed type 2 diabetes mellitus (T2DM) were enrolled in this study. According to the clustering classification method by Ahlqvist's team in Sweden, the newly diagnosed T2DM patients were classified to explore the characteristics of thyroid function and islet function in patients with different subtypes of T2DM. Methods A retrospective study was conducted to collect general data such as gender, age and clinical data such as thyroid function and islet function of 365 patients with newly diagnosed T2DM. Five variables including age at diagnosis, body mass index (BMI), glycated hemoglobin A1c (HbA1c), islet β cell function index (HOMA2-β) and insulin resistance index (HOMA2-IR) were used to perform K-means cluster analysis in newly diagnosed T2DM patients. The differences of thyroid function and islet function among different subtypes were compared. Results Before clustering and classification, the age at diagnosis, HOMA2-β, TSH, positive rate of thyroid antibody and prevalence of subclinical hypothyroidism in female patients were higher than those in male patients. The values of BMI, HbA1c, FPG and FT3 were lower than those in men. The above differences were statistically significant(P＜0.05). There was no significant difference in INS and CP between males and females(P＞0.05). After clustering and classification, the levels of T3 and FT3 in SIDD subtype patients were the lowest, and the levels of T4 and FT4 in MARD subtype patients were the lowest, and the differences were statistically significant(P＜0.05). However, there was no significant difference in the positive rate of thyroid antibodies and the prevalence of thyroid diseases among patients with different subtypes(P＞0.05). After clustering and typing, patients with SIDD had worse islet function and glucose control, and patients with SIRD had more severe IR. The 2hCP was the highest in patients with MARD subtype, while the 2hINS was higher in patients with SIDD subtype and lower in patients with MOD subtype, and the differences were statistically significant(P＜0.05). Conclusion After cluster typing, the characteristics of each subtype are stable, and the patients can be classified clearly. There is no significant difference in thyroid function among the subtypes, but there is significant difference in islet function among the subtypes