Malignant digestive system tumors are a leading cause of cancer-related deaths in China,drawing significant attention in clinical and basic research owing to their complex molecular mechanisms.B7-H4,a member of the B7 protein family within the immunoglobulin su-perfamily,exerts various biological functions,primarily inhibiting T-cell activation and proliferation and blocking cytokine synthesis,thereby suppressing the immune response.Overexpression of B7-H4 in various tumor tissues is closely associated with tumor cell proliferation,dif-ferentiation,apoptosis,invasion,metastasis,and correlates with patient prognosis.Despite its crucial role in tumor onset and progression,the specific mechanism of B7-H4 action remains unclear.This article reviews the research progress on B7-H4 in gastrointestinal tumors,aim-ing to provide new perspectives for future studies.