Objective To observe the serum cardiac troponin I (cTnI) level and to analysis the relations between the serum cTnI level and prognosis in patients with dilated cardiomyopathy (DCM) and Cardiac Dysfunction.Methods Serum cardiac cTnI level was measured by enzyme-linked immunosorbant assay. Results The serum cTnI level in DCM patients with class IV cardiac function (0.53 ±0.31) μg/L was significantly higher than in DCM patients with class Ⅲ cardiac function (0.45±0.27) μg/L.There was significantly difference in serum cTnI levels between DCM patients with class Ⅲ cardiac function and DCM patients with class Ⅱ cardiac function(0.29±0.27) μg/L.Conclusion The higher serum cTnI level is correlated with the severity of cardiac function and may be useful for evaluating prognosis in patients with DCM.