Abstract： ObJective To observe the efficay and adverse reactions of olmesartan combined with hydrochlorothiazide on patients with primary moderate hypertension,compared with the therapy of benazapril associated with amlodipine.Methods 116 primary moderate hypertension patients were randomly divided into the treatment group and control group.Patients in treatment group were treated with olmesartan combined with hydrochlorothiazide oral administration,and control group were given benazapril combined with amlodipine oral administration,which lasted for 3 weeks.Every subject was measured blood pressure before and after the drug administration and observed adverse reaction.Cardiac hypertrophy was detected by UCG.A comparison was made in effectiveness of the drug and cardiac hypertrophy between two groups.Results There was significant difference in effectiveness of two anti-hypertension therapies,and cardiac hypertrophy in the treatment group was lighter than that in control group.Conclusion The therapy of olmesartan combined with hydrochlorothiazide was more effective than that of benazapril combined with amlodipine,also more depressed cardiac hypertrophy.