This article reviewed inhibitory activities of green tea catechins (GTCs) against various tumorigenesis and their suppressive effects on cancer cell progression, metastasis, and angiogenesis according to a great number of kinds of literature, and then summarized the mechanisms of tea catechins-mediated cancer prevention in various cancer types. Special emphasis was placed on summarizing recent research highlighting the related techniques in improving GTCs' effectiveness in the prevention of tumor progression and/or treatment of cancers. Synergistic effects of catechins when combined with other phytochemicals and drugs, nanostructure- based delivery system, and molecular modifications of EGCG and catechins as means were discussed, and thus provide the basis to better utilize GTCs as the main ingredient of functional foods to reduce the risk of human cancer.