The invention relates to a dark green tea herbal drink and a preparation method of the dark green tea herbal drink. The dark green tea herbal drink is prepared from the following raw materials including black green tea, hawthorn, siraitia grosvenorii, lophatherum gracile, smoked plums, xylitol, honey and reverse osmosis pure water, wherein the black green tea, the hawthorn, the siraitia grosvenorii, the lophatherum gracile and the smoked plums are all measured after being dried; the raw materials including the black green tea, the hawthorn, the siraitia grosvenorii, the lophatherum gracile and the smoked plums are subjected to water extraction, wherein the black green tea is subjected to water extraction independently, leaching solutions are subjected to mixing, cooling and sedimentation, supernatant is collected, the xylitol and the acacia honey are added to the supernatant, the water is added to the mixture, the water and the mixture are mixed evenly at a constant volume, and the dark green tea herbal drink is obtained after filtration and sterilization. According to the dark green tea herbal drink and the preparation method of the dark green tea herbal drink, the compatibility of the raw materials in a formula is conducted in combination with theories of traditional Chinese medicine, various functions of the raw materials are preserved, damage of ingredients of the lophatherum gracile and other cold raw materials to the spleen and stomach is eliminated through intercoordination of the raw materials, and the prepared dark green tea drink tastes unique; since the extraction temperature is low, the situation that high temperature extraction causes a cooked taste and reduces leaching efficiency of tea polyphenols is avoided, and the effects that the taste is softened, functional components and natural fragrance are protected against damage are achieved.