Tea polyphenols are a general term for polyphenolic substances in tea leaves, which are white amorphous powders that are easily soluble in water, soluble in ethanol, methanol, acetone, and ethyl acetate, and insoluble in chloroform. The content of tea polyphenols in green tea is relatively high, accounting for 15% to 30% of its mass. The main components of tea polyphenols are flavonoids, anthocyanins, flavonols, anthocyanins, phenolic acids, and phenolic acids. Among them, flavanones (mainly catechins) are the most important, accounting for 60% to 80% of the total tea polyphenols, followed by flavonoids, and other phenolic substances have relatively low content.