Cardiac magnetic resonance T2* mapping technique is a gradient echoes relaxation recovery sequence, being used to measure the iron metabolism abnormality clinically, such as myocardial iron of hemorrhage in acute myocardial infarction reperfusion injury, transfusion-dependent anemia, hemochromatosis and so on, which is supposed to be the main quantitative evaluation method for myocardial iron overload or deficiency with critical clinical value. This paper summarizes the technical and post-processing points of cardiac magnetic resonance T2* mapping and its clinical applications in diseases related to abnormal myocardial iron metabolism.