Abstract: Objective To analyze the etiological classification and composition of 3 706 patients with secondary hypertension from 9 439 hypertensive inpatients of the Hypertension Department of Henan Provincial People’s Hospital from 2012 to 2016, so as to provide etiological reference for the prevention and treatment of hypertension, and improve the attention of clinicians to the screening of secondary hypertension. Methods A retrospective study was conducted to analyze the age, sex composition and etiological classification of 3 706 patients with secondary hypertension from 9 439 hypertensive inpatients. Results Essential hypertension accounted for 60.74%（5 733 cases） and secondary hypertension accounted for 39.26%（3 706 cases） of 9 439 hypertensive inpatients. Among the secondary hypertension patients, the most frequent cases were hypertension caused by psychological factors（1 175 cases, 31.70%）, followed by obstructive sleep apnea hypopnea syndrome（779 cases, 21.02%）, primary aldosteronism（728 cases, 19.64%） and renovascular hypertension（702 cases, 18.94%）. Compared with the patients with essential hypertension, the patients with hypertension caused by psychological factors, primary aldosteronism, renovascular hypertension, hypothyroidism and glaucoma were older, and the female patients with psychological factors hypertension and endocrine secondary hypertension were more（P＜0.05）. Compared with the patients with essential hypertension, the patients with secondary hypertension were older （50.2±15.0） vs（46.6±15.2）years and the proportion of male patients was smaller 54.6%（2 024/3 706） vs 64.5%（3 695/5 733）（both P＜0.05）. The average age of female patients with secondary hypertension and essential hypertension was significantly higher than that of male patients（P＜0.05）. Conclusion From 2012 to 2016, 39.26% of hospitalized patients with hypertension had secondary hypertension, which was higher than that reported in domestic and foreign literatures. The proportion of secondary hypertension caused by anxiety disorder and depression disorder was the highest. Obstructive sleep apnea hypopnea syndrome, primary aldosteronism and renovascular hypertension were also the common causes of secondary hypertension. Secondary hypertension was also screened out in older hypertensive patients.