C-peptide, as the decomposition product of insulin, is commonly used to evaluate the degree of insulin resistance in clinical practice. However, in recent years, many studies have shown that C-peptide is involved in the formation and development of atherosclerosis. In addition, for patients with hypertension complicated with type 2 diabetes mellitus, insulin resistance is the main factor that hypertension and type 2 diabetes mellitus jointly promote atherosclerosis. Further exploration of serum fasting C-peptide and atherosclerotic plaque has important clinical significance for early intervention, prevention of cardiovascular and cerebrovascular events and improvement of prognosis in patients with hypertension and type 2 diabetes mellitus