The RAAS system, the renin angiotensin aldosterone system, has the main role of regulating blood pressure and water-electrolyte balance and maintaining the relative stability of the body’s internal environment. The renin angiotensin aldosterone system is an important mechanism involved in the pathogenesis of hypertension, and excessive activation of the renal master angiotensin aldosterone system is one of the reasons for the formation of hypertension. Clinically, blood pressure can be controlled by inhibiting the RAAS system. Commonly used drugs include vasoconverting enzyme inhibitors, such as enalapril, captopril, fosinopril, etc., and vasoconverting enzyme receptor blockers, such as valsartan, corsartan irbesartan, etc. The levels of renin, angiotensin II and aldosterone can also be monitored clinically to identify primary and secondary hypertension.