The application of PET/CT for early diagnosis of patients with malignant tumors is particularly important for their prognostic assessment. ¹⁸F-fluorodeoxyglucose (FDG) is currently the most commonly used positron imaging agent of PET/CT in nuclear medicine. It has great advantages in the differentiation of benign and malignant lesions, evaluation of the curative effect of malignant tumor treatment, and the preoperative evaluation of diseases, thus becoming an indispensable imaging aid for clinical diagnosis. But its application also has some inconveniences, such as the requirements of blood glucose and fasting for patients. In addition, the physiological uptake of brain and gastrointestinal tract may also affect clinicians to make correct diagnosis in varying degrees. By contrast, ⁶⁸Ga-labeled fibroblast activation protein inhibitor (FAPI) is a new type of positron imaging agent targeting fibroblast activation protein. Its high T/NT and no additional requirements like fasting or bed rest for patients make it a hit in the research field. This paper reviews the target mechanism and clinical application of ⁶⁸Ga-FAPI.