Abstract: Aim: To compare the effects of losartan and captopril on essential hypertension. Methods: Fifty nine patients were treated with losartan, 50 mg～100 mg/d; fifty six patients were treated with captopril 25 mg～75 mg/d for six weeks for comparison. Blood pressure were monitored , blood lipid, urea nitrogen, creatinine, urine acid, blood α 1 MG, and urine α 1 MG,and urine Alb, plasma renin activity （PRA） were examined before and after treatment. Results:There are no difference in the antihypertensive effect between the two drugs.than captopril group. Losartan had no effect on TG and TC, it decrease the level of urine acid; the incidence of cough is lower than that of captoril. Losartan could decrease blood α 1 MG and urine α 1 MG and urine Alb （P ＜0.001）, while plasma renin activity （PRA） was increased（ P ＜0.001）. Conclusion:Losartan is effective and safe in treatment of hypertension, and it can decrease the level of urine acid of blood. The incidence of cough is lower than that of captoril.