Abstract: Objective To explore the influence of irbesartan and metoprolol on the ambula-tory blood pressure of patients with hypertension.Methods 80 patients with primary hypertension were selected and randomly divided into irbesartan group and metoprolol group,40 cases in each group.24 hours ambulatory blood pressure monitoring (ABPM)before treatment and 3 months af-ter treatment was conducted,and pressure control was observed in both groups.Results Before treatment,there was no significant difference of blood pressure between two groups,and blood pressure decreased significantly after treatment,and mean 24 hours diastolic blood pressure (DBP) at night after treatment did not change greatly.There were significant differences of 24 hours sys-tolic blood pressure (SBP),24 hours DBP,SBP and DBP at daytime and night,which decreased much more significantly in irbesartan group than in metoprolol group.Conclusion Irbesartan and metoprolol both have a favorable anti-hypertensive effect on primary hypertension,but irbesartan is more effective.