Since ancient times, there are a number of different methods of classifying tea. Tea can be classified by tea processing technology, origin, season, level, shape, or sales. In morden China, according to the different degree of fermentation of tea and tea processing, tea was divided into non-fermented tea, semi-fermented tea, and fully-fermented tea, and divided tea into six basic teas and re-processing tea, namely: green tea, black tea, Oolong tea, yellow tea, white tea and dark tea and re-processing tea, that is, scented tea and so on.