Iron, as necessary trace element in the human body, was associated with tumorigenesis and development. The free radicals coming from the process of oxidation and reduction cycle of iron, caused harmful effects, such as tumorigenesis. Besides, abnormal iron metabolism increased the risk of tumorigenesis and promotes tumor growth. Ferritin, a glycoprotein synthesized by the liver, played an important role in the balance of iron metabolism. Combined with the free iron, ferritin prevented from toxic effects of high intracellular concentration of free iron. Serum ferritin was a main indicator of iron storage in the body, and the expression levels of ferritin are increased in majority patients with cancer. Furthermore, ferritin was also involved in tumorigenesis and development by anti-oxidative damage, angiogenesis, immunosuppression and promoting cell proliferation. The survival of patients with high expression of ferritin was worse, suggesting that it could be used as prognostic indicator of cancer patients. On the other hand, the down-regulated expression of ferritin could not only inhibit the proliferation of cancer cells, but also increased their sensitivity to chemotherapy. It was implicated that ferritin may have potential in treatment of cancer. Although many new findings have led to a further understanding of ferritin, further research is needed to shed new light on the role of ferritin. In this review, we aim to provide an overview about the clinical significance of ferritin and its further application in the treatment of cancer, based on the recent advances in tumorigenesis mechanism of ferritin, and the studies of correlation between its expression and prognosis.