BACKGROUND: It is significant to establish a kind of effective, conve nient and reliable animal model of hypertension. At present, dogs, rats and rabbits are usually used to establish hypertensive models at home and abroad, and the renal artery stenosis induced hypertensive models are ex tensively used to research hypertension and its complication for human be ings because they are convenient and reliable, and there are many methods to establish them, but the effects are to be evaluated. OBJECTIVE: To establish convenient and reliable animal models of ex perimental renal artery stenosis induced hypertension. DESIGN: A randomized grouping design and animal experiment. SETTING: Institute of Cerebrovascular diseases, Medical College Hospital of Qingdao University. MATERIALS: The experiments were carried out in Shandong Key Labora tory for Prevention and treatment of Brain Disease from September 2005 to February 2006. Eighty-one healthy Wistar rats divided into 7 groups accord ing to the method of random number table: unilateral renal artery stenosis group (n=18), bilateral renal artery stenosis group (n=17), unilateral renal artery ligation group (n=15), bilateral renal artery ligation group (n=15), uni lateral renal artery stenosis sham-operated group (n=6), bilateral renal artery stenosis sham-operated group (n=4) and normal control group (n=6). METHODS: Unilateral renal artery stenosis group: Right renal artery was clamped with miniature silver clip, and left kidney was resected after 12 days. Bilateral renal artery stenosis group: Right renal artery was clamped with miniature silver clip, and the same treatment was given to the left side after 12 days. Unilateral renal artery ligation group: Right renal artery was ligated with filament, and left kidney was resected after 12 days. Bilateral renal artery ligation group: Right renal artery was ligated with filament, and the same treatment was given to the left side after 12 days. Unilateral renal artery stenosis sham-operated group: Right kidney was exposed, and returned to the original place without any treatment, and left kidney was resected af ter 12 days. Bilateral renal artery stenosis sham-operated group: Right kid ney was exposed, and returned to the original place without any treatment, and the same treatment was given to the left side after 12 days. Normal con trol group: The rats were not given any treatment. The blood pressure and heart rate were determined with RBP-2 hemomanometer for rats. MAIN OUTCOME MEASURES: The successful rate of model estab lishment, blood pressure and heart rate were observed. RESULTS: Totally 81 rats were used, and 61 of them died, all were in volved in the analysis of results without deletion. ① Blood pressures in the unilateral and bilateral renal artery stenosis groups and bilateral renal artery ligation group were obviously higher than those in the normal control group and bilateral renal artery stenosis sham-operated group [(138.0 ±36.5), (154.2±11.6), (160.5±0.7), (101.3±17.6), (108.3±5.7) mm Hg]. ② The changes of heart rate in the renal artery stenosis group were unstable, and the heart rates in the unilateral and bilateral renal artery stenosis groups, bilateral renal artery ligation group, normal control group and bilat eral renal artery stenosis sham-operated group were (367.5±47.2), (420.2 ±47.8), (386.0±4.2), (390.3±42.4), (417.3±27.5) beats per minute, respec tively. ③ The survival rates in the renal artery stenosis groups (22%, 29%) were significantly higher than those in the renal artery ligation groups (0,12%), and it was the highest in the unilateral renal artery stenosis group.CONCLUSION: The method of clamping bilateral renal arteries can establish stable rat models of hypertension induced by renal artery stenosis.