Black oolong, also known as oil-cut black oolong tea, belongs to a kind of commercial oolong tea. Since Suntory Company of Japan introduced black oolong tea beverage products in 2009, black oolong tea beverage has entered people's lives. The selling point of black oolong tea beverage is that the content of tea polyphenols is twice that of ordinary commercial oolong tea, which has the effects of detoxification, inhibiting fat absorption and promoting oil discharge. It was found that most black oolong teas were made from oolong teas aged 1~2 years by high-temperature baking, but high-temperature baking could not increase the content of tea polyphenols, and catechins in tea polyphenols would be oxidized and polymerized to form o-quinone after high-temperature baking. Selling point of black oolong tea beverage: the content of tea polyphenols is twice that of ordinary commercial oolong tea. Efficacy: detoxification, inhibition of fat absorption and promotion of oil discharge.