Objective To investigate the relationship between the expression of insulin-like growth factor-1 (IGF-1), insulin-like growth factor binding protein-3 (IGFBP-3) and hypothyroidism in patients with type 2 diabetes mellitus (T2DM). Methods A total of 63 patients with simple T2DM who visited our hospital from January 2022 to March 2023 were collected as the T2DM group, 60 patients with T2DM accompanied by hypothyroidism during the same period were selected as the study group, and 60 healthy individuals were regarded as the health group. The general information and biochemical indicators of the subjects were collected, enzyme linked immunosorbent assay was applied to detect serum levels of IGF-1 and IGFBP-3, chemiluminescence was applied to detect free triiodothyronine (FT3), free thyroxine (FT4), thyroid hormone (TSH), thyroid peroxidase antibody (TPOAb), anti-thyroid autoantibodies (TgAb). Pearson correlation coefficient was applied to analyze the correlation between IGF-1, IGFBP-3 and other indicators; Logistic regression was applied to analyze the influencing factors of hypothyroidism in T2DM patients. Results BMI, FPG, 2h PG, FINS, HbAlc, TC, TG, LDL, Cr, BUN, UA, TSH, TPOAb, TgAb in the study group and T2DM group were obviously higher than those in the healthy group, while HDL, FT3, FT4, IGF-1, and IGFBP-3 were lower than those in the healthy group (P＜0.05); the levels of FPG, HbAlc, TC, TG, LDL, BUN, UA, TSH, TPOAb, and TgAb in the study group were obviously higher than those in the T2DM group, while levels of HDL, FT3, FT4, IGF-1, and IGFBP-3 were lower than those in the T2DM group (P＜0.05). The serum IGF-1 and IGFBP-3 in the study group were negatively correlated with FPG, FINS, HbAlc, TC, TSH, and TgAb (P＜0.05). FPG, HbAlc, TC, TSH, IGF-1, and IGFBP-3 were influencing factors for the occurrence of hypothyroidism in T2DM patients (P＜0.05). Conclusion Patients with T2DM and hypothyroidism have abnormally low levels of serum IGF-1 and IGFBP-3, which are closely related to the occurrence of hypothyroidism