Abstract: 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 superfamily, 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, differentiation, 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, aiming to provide new perspectives for future studies.