Abstract: As a kind of specific water- soluble pigments in nature,anthocyanidin has a typical B ring o- diphenol molecular structure and is easily combined with different kinds of monoses,disaccharides,trisaccharides to be anthocyanin.Anti- tumor activities and their molecular mechanisms of six common anthocyanidin monomers and their anthocyanin monomers were reviewed,in order to clearly explain the chemical mechanisms of anti- tumor activities of plant anthocyanin extracts from nature,and to be helpful in the potential clinical anti- tumor application and further fundamental anti- tumor activities researches.