Objective To investigate the expression of connective tissue growth factor (CTGF) in the myocardium of spontaneously hypertensive rats and its relationship to the hypertensive myocardial fibrosis. Metheds The investigative rats comprised normotensive control(WKY) and hypertensive groups(SHR), of which blood pressure, collagenic content and the expression of CTGF in the left ventricular were measured at 14-and 28-week-old, respectively. CTGF and TGF-β1 were evaluated by qualitative and semiquantitative immunohistochemical staining and semiquantitative reverse transcription polymerase chain reaction. MASSON staining was used in the study of total collagen in left ventricular interstitial tissue. Results Compared with the WKY, the collagen volume fraction (CVF)、perivascular collagen area (PVCA)、and the expression of CTGF, TGF-β1 and the mRNA of them in left ventricular were significantly increased in SHR (P 0.05). CTGF reacted primarily with myocardial interstitium, artery intimal and vascular smooth muscle. Corrective analysis revealed that CTGF positively correlated with TGF-β1(r=0.562, P 0.05), CVF(r=0.715,P 0.01)and PVCA(r=0.786, P 0.01).Conclusion CTGF may play important roles in developement of myocardial interstistisl fibrosis.