Digestive tract cancer is one of the most common types of cancers globally, with ~4.8 million new cases and 3.4 million cancer‑associated deaths in 2018, accounting for 26% of cancer incidence and 35% of cancer‑related deaths worldwide. S100 protein family is involved in regulating cancer cell proliferation, angiogenesis, epithelial‑mesenchymal transition (EMT), metastasis, metabolism and immune microenvironment homeostasis. The critical role of S100 protein family in digestive tract cancer involves complicated mechanisms, such as cancer stemness remodeling, anaerobic glycolysis regulation, tumor‑associated macrophage differentiation and EMT. The present study systematically reviewed published studies on the compositions, function and the underlying molecular mechanisms of the S100 family, as well as guidance for diagnosis, treatment and prognosis of digestive tract cancer. Systematic review of the roles and underlying molecular mechanisms of S100 protein family may provide new insight into exploring potential cancer biomarkers and the optimized therapeutic strategies for digestive tract cancer.