Primary and secondary hypertension have their different characteristics in terms of incidence rate, etiology, prevalent population and treatment modalities. 1. Incidence rate: among all hypertensive patients, primary hypertension patients account for the majority, and secondary hypertension patients are fewer. 2. Etiology: Primary hypertension has no exact etiology, and is the result of a combination of genetic and environmental factors. Secondary hypertension often has other primary diseases, such as primary aldosteronism, pheochromocytoma, renal vascular hypertension, aortic constriction and so on. 3. Prevalent population: primary hypertension occurs in the elderly, secondary hypertension can occur in young patients. 4. Treatment: Primary hypertension can be well controlled by antihypertensive drugs. Patients with secondary hypertension usually cannot lower their blood pressure to normal by taking antihypertensive drugs, and need to treat the primary disease in order to lower their blood pressure. Hypertensive patients should go to the hospital in time, improve the examination, exclude secondary factors, under the guidance of the doctor for regular treatment.