Objective：Cardiac magnetic resonance imaging(CMR)was used to analyze the imaging features of the rat model of myocardial fibrosis，and to explore the correlation between MR T2WI findings and pathological changes of myocardial fibrosis. Methods：Fifty SD rats were randomly selected，forty mice were randomly selected and subcutaneously injected with five mg/kg isoproterenol for ten days to establish the myocardial fibrosis model，and ten rats were subcutaneously injected with the same dose of normal saline for ten days as the control group. The model group was divided into three subgroups，and in vivo imaging scan was performed on day five，seven，and nine with 7.0 T magnetic resonance equipment，respectively. The control group was scanned on day seven and the contrast noise ratio(CNR)was calculated. The HE and Masson staining were performed to observe the structural changes of myocardial tissues and calculate the collagen volume fraction(CVF). Results：36 rats in the model group and 10 rats in the control group were included in statistical analysis. The CNR of the model group(15.26 ± 1.93)and the control group(3.56 ± 0.93)showed statistically significant differences(P＜0.01). Compared with the control group，the left ventricular lumen of the model group was enlarged，the left ventricular wall showed T2WI hyposignal changes，and the thickness of the ventricular wall decreased and became thinner. The left ventricular wall thickness of the control group was(2.73±0.23)mm，which was statistically significant compared with that of the model group(1.19±0.29)mm(P ＜ 0.01). These indicated fibrotic changes in the ventricular wall.The CVF of the control group(6.18% ± 2.90%)was significantly different from that of the model group(43.06% ± 6.59%)(P ＜ 0.01). The value of phase relationship between CNR and CVF was 0.993，showing a significant positive correlation. Conclusion：The MR T2WI of the myocardial fibrosis model of rats is characterized by obvious pathological imaging characteristics，which could be used to carry out imaging and clinical research of myocardial fibrosis.