This study aimed to investigate the effects of rosuvastatin on TGF-β1 expression, cardiac fibrosis, ventricular remodeling and cardiac function in diabetic cardiomyopathy rats. Twenty-seven diabetic rats induced by streptozotocin intraperitoneal injection were randomly divided into three groups, viz. diabetic, rosuvastatin low-dose (Ros-L) and high dose group (Ros-H). Intervention group were given rosuvastatin 2 mg/kg/d and 5 mg/kg/d orally, respectively. After 10 weeks, the levels of glycosylated hemoglobin (HbA1c), creatine phosphokinase isoenzyme (CK-MB), plasma brain natriuretic peptide (BNP), myocardial collagen volume fraction (CVF) and left ventricular mass index (LVWI) were measured. CK-MB levels in Ros-H and Ros-L rats were lower than in the diabetic group. Rosuvastatin alleviated myofibrosis cordis and fibroplastic proliferation. LVWI, BNP, CVF and TGF-β1 mRNA and protein levels in the diabetic group were higher than in the control, but were reduced after rosuvastatin treatment. These results demonstrate that rosuvastatin dose-dependently reduces TGF-β1 expression and inhibits the development of myocardial fibrosis in diabetic cardiomyopathy.