Objective To explore the network remodeling of collagenⅠand Ⅲ protein in the heart of renal hypertension rats. Methods The animal model was prepared by bilateral renal artery stenosis. Thirty-two SD rats were randomly divided into sham operation group, two weeks group, five weeks group and seven weeks group after operation. The model quality of hypertensive rats was assessed with noninvasive blood pressure analysis. The variation characteristics of collagenⅠand Ⅲ in left ventricular wall were detected by immunohistochemistry and Western blotting, and the quantitive analysis was performed with the microscopic image analysis system. Results BR>The collagenⅠand Ⅲ networks had no noticeable change at the second week after operation, but at the fifth week after operation,the thick fibers of collagenⅠaround cardiomyocyte bundle were seen markedly broken and gathered together, or absent. The broken or accumulated fibers with irregular arrangement in collagenⅠsheath in tunica adventitia of arteriole were also detected. The thick and thin fiber bundles of the collagen Ⅲ around cardimyocyte became loose and disorder at the fifth week after operation, and the collagen Ⅲ sheath of tunica adventitia of arteriole turned to be loose. The results of microscopic image analysis showed that the difference of the mean optical density value and the average area ratio of collagen I had both significance between the fifth week and the seventh week after operation ( EM>P /EM><0.05). The difference of mean optical density value of collagen Ⅲ had no significance between groups ( EM>P/EM> >0.05), and the difference of the average area ratio had significance between the second week and the fifth week group after operation (EM>P /EM><0.05). The results of Western boltting showed that the expression level of collagen I was gradually increased, and collagen Ⅲ was gradually decreased from the fifth week after operatio