Why are patients with hypertension prone to co-existing diabetes mellitus. Patients with hypertension complicated by diabetes, especially those who are also obese, often share a common pathophysiological feature, which is insulin resistance. How does insulin resistance occur? In people with essential hypertension, there are many patients with higher than normal blood glucose levels and plasma insulin levels. As we all know, insulin is a hypoglycemic hormone, so why the plasma insulin level is high but can not lower blood sugar, the problem is that these people have resistance to insulin in the body, so that it can not exercise its ability to lower blood sugar. Excessive insulin secretion is bound to cause hyperinsulinemia. Hyperinsulinemia promotes renal tubular sodium reabsorption, sympathetic excitation, accelerated heart rate, increased vascular resistance, elevated blood lipids, narrowing of arterial vascular sclerosis, and increased intracellular calcium ion concentration and sensitivity to elevated substances, leading to hypertension. Due to the resistance to insulin in the patient’s body, it is difficult for the pancreas to withstand the heavy pressure of long-term high load, and eventually it is exhausted and its function gradually decreases or even fails, and it is unable to secrete insulin, so the blood sugar in the body rises sharply, causing diabetes. High blood pressure and diabetes interact with each other, pushing the wave, the patient’s body sugar and fat metabolism further disorder, continuous high blood sugar on the cells to produce toxic, accelerated atherosclerosis, so kidney disease, cardiovascular and cerebrovascular disease, endangering the lives of patients. Diabetic patients, because of the disorder of sugar metabolism, prompting certain components of blood and tissue glycation, will accelerate and aggravate the formation of atherosclerosis. Hypertensive patients due to fat accumulation, blood vessel wall thickening and hardening, elasticity loss, etc., will lead to local tissue ischemia and hypoxia, will also contribute to the aggravation of diabetes. Therefore, hypertensive patients, especially obese ones, should be alert to the occurrence of diabetes, regularly check their blood glucose, and provide timely treatment for combined diabetes. It can be seen that there is a close relationship between hypertension and diabetes mellitus in terms of pathogenesis. Therefore, hypertensive patients should have regular medical checkups, check blood sugar and blood lipids, and disable antihypertensive drugs that aggravate insulin resistance if high blood sugar and plasma insulin levels are found. In general, pay attention to health care, obese people appropriate weight loss, do not smoke and alcohol, emotional stability, regular life.