Polyphenols are secondary metabolites that presented abundant in human diet such as ce-reals, fruits, vegetables, legumes and beverages. There are four main classes of polyphe-nols, including phenolic acids, flavonoids, stilbenes, and lignans. Beneficially, phenolics have antioxidant properties which have been discovered for decades. The exertion of these antioxidant effects may be various and depends on the characteristics of food composition and minor components of antioxidants. There are some potential mechanisms of polyphenol antioxidative action have been suggested. The free radical scavenging and capability to chelate with transition metals are important antioxidative mechanisms of polyphenols. This paper provides information about the plant polyphenols, events related to the classification and mechanism of antioxidant activity of them