Fibroblast activation protein inhibitor (FAPI) has been the focus of nuclear medicine since its introduction. With the in-depth study of FAPI tracer, its clinical application in various non-malignant diseases has also been gradually reported. Many studies have confirmed its uptake in a variety of non-malignant diseases, which indicate that FAPI tracers have good application prospects. This article reviews the latest research status and clinical application of radiolabeled FAPIs in cardiovascular diseases, rheumatic immune diseases, immunoglobulin (Ig)G4-related diseases, renal fibrosis and other non-malignant diseases at home and abroad.