Abstract: Objective To build a rat model of right ventricular failure （RVF） by subcutaneous injection of Monocrotaline. Methods Forty Wistar rats were equally divided into four groups, 10 rats each group. Exp4 group: four weeks after Monocrotaline injection, experimental results were observed; Exp6 group: six weeks after Monocrotaline injection, experimental results were observed; Con4 group: four weeks after normal saline injection, experimental results were observed; Con6 group: six weeks after normal saline injection, experimental results were observed. Four and six weeks after Monocrotaline or normal saline injection respectively, the hemodynamic indexes of each pair of groups were measured. Their hearts and livers were excised to measure physiological indexes and had pathological examinations. Results Mean pulmonary arterial pressure (MPAP), maximal rate of change of right ventricular pressure (RV dp/dtmax) and right ventricular ypertrophy index in Exp4 group were higher than those in Con4 group（Plt;0.05,0.01）. Compared with Con6 group, there were obvious symptoms of RVF in Exp6 group which included the increases of heart rate, increases of central venous pressure (CVP) and MPAP, the decreases of RV dp/dtmax, the decreases of weight, the increases of liver weight/body weight ratio and right ventricular hypertrophy index, significant pleural and peritoneal effusions（P＜0.05,0.01 ）. Pathological examination of Exp6 group showed disordering and bifurcated cardiac muscle fibers, large and thickly dying cell core, enlarged transverse diameter of the cardiac muscle fibers and stroma fibrosis. Vacuolar degeneration and dissolved carcoplasm could be seen. The vessel wall of the lung arteriole thickened, intercellular layer smooth muscle cell hyperplasied, elastic fibers increased, vessel wall arteriosclerosised, lumens stenosized. Conclusion This model is simple to build and successful rate is high. It is valuable for further research.