Abstract: Objective: To explore the effects of taking medicine in different time on the rhythm of blood pressure of elderly patients with hypertension. Methods: One hundred and twenty elderly patients with hypertension were randomly divided into treatment group and control group. The treatment group were treated with felodipine in the morning and enalapril in the evening by oral, the control group were treated with felodipine and enalapril in the morning by oral. The ambulatory blood pressure in two groups were monitored before treatment and after taking medicine 8 weeks, the rhythm of blood pressure of which was compared. results: The blood pressure of both groups before eatment and after taking medicineat 8 weeks were obviously lower than that in taking medicines(P ＜ 0. 01) , the falling range of diastolic pressure at day，blood pressure at night, 24 h SBP and blood pressure in the morning of the treatment group were better than those in control group(P ＜ 0. 05 to P ＜ 0. 01) . The proportion of non dipper type patients in two groups before treatment were 89. 2% and 89. 1%, and 50. 8% and 72. 7% after treatment, respectively. The improvement of rhythm of blood pressure in treatment group was significantly better than that in control group(P ＜ 0. 05) . Conclusions: The different taking medicine styles can significant improve the rhythm of blood pressure and protect target organ of elderly patients with hypertension.