Abstract: Objective To observe the influence of different antihypertensive drugs combination on senile hypertension patients blood pressure variability. Methods From January 2015,to January,2016,128 cases of patients with senile primary hypertension in our hospital were chosen and randomly divided into A and B two groups(64 cases in each group).Group A were given 5 mg/d amlodipine and 4 mg/d perindopril,while group B were given 4 mg/d perindopril and 25 mg/d hydrochlorothiazide.Before taking the medicine and 8 weeks later noninvasive portable ambulatory blood pressure monitors were used to test 24 h ambulatory blood pressure (systolic blood pressure and dynamic diastolic blood pressure),and measure value coefficient of variation CV as an indicator of BPV. Results Eight weeks after taking medicine, indexes including 24 h mean systolic blood pressure(24hSBP),day mean systolic blood pressure(dSBP), night mean systolic blood pressure(nSBP),24 h mean systolic blood pressure coefficient of variation (24hSCV),day mean systolic blood pressure coefficient of variation (dSCV) and night mean systolic blood pressure coefficient of variation (nSCV) were significantly lower than that in group B(P<0.05).Eight weeks after taking medicine,24h mean diastolic blood pressure (24hDBP) day mean diastolic blood pressure (dDBP),night mean diastolic blood pressuren (DBP) in the two groups had no statistically significant difference(P>0.05).In the A group, 24 h mean diastolic blood pressure coefficient of variation (24hDCV),day mean diastolic blood pressure coefficient of variation (dDCV) and night mean diastolic blood pressure coefficient of variation(nDCV) were significantly lower than in the B group (all P<0.05).In group A,nitric oxide were significantly higher than that in group B,and while endothelin level was significantly lower than that in group B(P<0.05). Conclusion Amlodipine combined with perindopril and perindopril combined with hydrochlorothiazidel could all effectively reduce the elderly patients with essential hypertension blood pressure variability,but amlodipine combined with perindopril has more obvious effects.