Aim To assess myocardial fibrosis with ultrasonic backscatter measurement combined with collagen metabolite in ischemia/reperfusion （I/R） injury canine. Methods 12 adult mongrel dogs were randomly divided into 2 groups: sham operation group （sham group） and ischemia/reperfusion group （I/R group）,6 dogs in each group. Integrated backscatter （IBS） and cyclic variation of integrated backscatter （CVIB） were detected in ventricular septal and posterior wall of the left ventricular with quantitative analysis of ultrasonic backscatter. Serum levels of connective tissue growth factor （CTGF） and aminoterminal propeptide of type Ⅰ procollagen （PⅠNP） were examined by enzyme-linked immunosorbent assay （ELISA）. Myocardial fibrosis of ventricular myocardium was tested by Masson staining,and expression of collagen Ⅰ was detected with pathologic immunohistochemistry. Results Compared with sham group,CTGF and PⅠNP levels were increased,IBS significantly was enlarged,and CVIB significantly was decreased in I/R group,the differences were statistically significant （P<0.05）. CTGF and PⅠNP levels were positively correlated with IBS and negatively correlated with CVIB in I/R group （P<0.05）. Masson staining showed that myocardial fibrosis was significantly increased and expression of collagen Ⅰ protein was strongly positive in I/R group. Conclusions IBS is increased,CVIB is decreased,and CTGF and PⅠNP levels were increased in ischemia/reperfusion injury canine. Myocardial fibrosis was involved in I/R damage to induce ventricular remodeling. Ultrasonic backscatter measurement combined with collagen metabolites could be an early and non-invasive method to examine ventricular fibrosis degree at I/R stage.