Abstract: Myocardial fibrosis is a common endpoint in almost all cardiovascular diseases following myocardial injury from various causes. Myocardial fibrosis is a key target for clinical diagnosis, risk stratification and treatment of cardiovascular disease. Therefore, early detection of myocardial fibrosis is very important for individualized treatment strategy decision-making and finally to improve patient outcome. Radionuclide-labeled fibroblast activation protein inhibitors (FAPIs) targeting fibroblast activation protein (FAP) are able to in vivo visualize cardiac fibroblast activation and assess pro-fibrotic activity, which is highly promising for applications in cardiovascular diseases. The authors systematically reviewed the current status, prospects and outlooks of related research in cardiovascular diseases.