Fibroblast activation protein(FAP),a kind of transmembrane glycoprotein in the serine protease family,has an activity similar to dipeptidase and gelatinase.It is expressed in the stroma of a variety of human tumors and is involved in different signaling pathways.It promotes the proliferation,migration,and invasion of tumor cells through a variety of mechanisms.Therefore,it is closely related to the poor prognosis of many tumors.However,current studies have not systematically elucidated the expression of FAP in gastrointestinal malignancies,and research on its specific mechanism of action and role as a tumor biomarker and therapeutic target are still in the initial stage.In this article,the role and mechanism of FAP in the occurrence and progression of gastrointestinal malignancies are reviewed,in order to provide ideas for predicting the prognosis of gastrointestinal malignancies and selecting new therapeutic targets.