Objective To investigate the roles of T GFβ1 and TGFβ1 typeⅠrecepter(TβRⅠ) in development of myocardial hypert rophy and myo cardial interstitium remodelling in renovascular hypertensive rat. 　Methods TGFβ1 and TβRⅠwere evaluated by qualitative and semi -qu antitative immunohistochemical staining to explore their distribution and ex peression in left ventricular tissue. Van Gieson staining were used in the stud y of total collagen in left ventricular interstitial tissue. 　Results Compared with sham-operated rat(SOR),the expression of T GFβ1 andTβRⅠ in left ventricular tissue were significantly increased in RHR(P <0.01 all). In RHR the antibody to TGFβ1 reacted primarily with cytoplasma a nd myo cardial interstitium while antibody to TβRⅠreacted mainly with myocyte membran es with weak labeling in myocardial interstitium. In SOR,very mild labeling for TGFβ1 and TβRⅠin myocardiun was found with no labeli ng in myocardial interstitium. Correlative analysis revealed that TGFβ1 or T βRⅠ was positively correlated with left ventricular mass index(LVMI),negativel y correlated with grey level of myocardial total collagen. Conclusions TGFβ1 and TβRⅠmay play important roles in develo pment of left ventricular hypertrophy and myocardial interstitial fibrosis.