How to rule out secondary hypertension, secondary hypertension is due to a certain disease causing high blood pressure, common causes of secondary hypertension are as follows: 1, adrenal causes, adrenal causes of hypertension is recommended to perform adrenal CT. 2, renal arterial, renal arterial causes are recommended to perform renal artery ultrasound and give renal artery CT if necessary. 3, nephrogenic, mainly seen in renal insufficiency, chronic nephritis, nephrotic syndrome. 4, cervical hypertension, cervical hypertension caused by sleep apnea syndrome, this condition is recommended to perform sleep respiratory monitoring. 5, cervical hypertension, cervical spine film, if necessary to give sleep respiratory monitoring. 4, sleep apnea syndrome caused, in this case it is recommended to perform sleep respiratory monitoring. 5, cervicogenic hypertension, cervicogenic hypertension can be performed cervical spine film, if necessary to give cervical spine nuclear magnetic can confirm the diagnosis.