Aim The preclinical studies of a novel angiotensin Ⅱ receptor 1 antagonist 2(4((1,7′dimethyl2′propyl1H ,3 ′H2,5 ′bibenzo [d] imidazol3 ′yl) methyl)1Hindol1yl) benzoic acid (intesartan).Methods The affinity to AT1 receptor of intesartan was tested through radioactive receptor binding assay by γcounter.The antihypertensive activity in spontaneously hypertensive rats (SHRs) at different doses in vivo was tested by tail noninvasive arterial blood pressure measurement system.Pharmacokinetic parameters were analyzed by high performance liquid chromatography (HPLC) method.Besides, acute toxicity tests in ICR and Ames reverse mutation assay in tester strain (TA97, TA98, TA100 and TA102) was also detected.Results The binding assays suggested that intesartan displayed high affinity to angiotensin Ⅱ AT1 receptor with an IC50 value of (0.36 ± 0.18) nmol· L1.In vivo antihypertensive experiments showed that intesartan had an efficient and longacting effect in reducing blood pressure which could last more than 24 h at the doses of 2 mg · kg1, 5 mg · kg1, and 10 mg · kg1 in spontaneously hypertensive rats.The minimum effective dose of it was 2 mg · kg1 and the T/P value was 54.18%.Acute toxicity tests suggested that intesartan was safe with the LD50 value of 526.20 mg · kg1.Ames assay proved that it would not cause the mutations of salmonella typhimurium.And the pharmacokinetic experiments showed that it could be absorbed efficiently and metabolized smoothly both in blood and in tissues in wistar rats.Conclusions Intesartan could be considered as a novel antihypertension candidate with efficient, longacting and low toxicity chracteristics.