Objective: To explore the correlation between changes of D-Dimer (D-D) and thyroid stimulating hormone (TSH) levels and vascular complications in patients with type 2 diabetes mellitus (T2DM). Methods: A total of 90 patients with T2DM admitted to the hospital were enrolled between January 2024 and January 2025, including 30 cases with simple T2DM in group A, 30 cases with T2DM and microvascular lesions in group B and 30 cases with T2DM and macrovascular lesions in group C. The clinical basic data, biochemical indexes, D-D and TSH in different groups were compared. The evaluation value of D-D and TSH in vascular complications was assessed by receiver operating characteristic (ROC) curves. Results: There was no significant difference in gender among the three groups (P<0.05). The age of patients in groups B and C was older than that in group A, BMI in group B was lower than that in group A, and course of diabetes mellitus in group C was longer than that in groups A and B, the differences were statistically significant (P<0.05). In group A, group B and group C, FBG and HbAlc were gradually increased (P<0.05), levels of D-D and TSH were also gradually increased (P<0.05). AUC values of D-D, TSH and combined detection in the diagnosis of vascular complications were 0.708, 0.683 and 0.749, respectively (P<0.05). Conclusion: The levels of D-D and TSH are closely related to vascular complications in patients with T2DM. D-D and TSH may be applied as biomarkers to predict vascular complications, which provides reference for early clinical intervention.