An application of a high-intensity focused ultrasound system to treatment of essential hypertension. A treatment process includes: conducting ultrasonic positioning measurement on both sides of perirenal fat tissue of a patient, setting a therapeutic window and parameters of the system, and setting corresponding power parameter of the system, so as to make local temperature of the tissue during treatment reach 40-70° C., wherein treatment portions are both sides, and treatment scope is one third to all of the whole tissue starting the system to treat one side of the tissue according to the set parameters and then the other. By treating a secondary center for regulating the activity of a whole-body sympathetic system, the activity of the whole-body sympathetic system can be reduced, so that the blood pressure level of the patient can be reduced, and fewer kinds and smaller dosage of antihypertensive drugs can be taken or ceased.