The invention provides sour tea with a hypoglycemic effect and a preparation method thereof, and the preparation method comprises the following steps: S1, preparing an
organic fertilizer, and planting tea seedlings by using the
organic fertilizer; s2, after the
tea tree grows to be mature, picking fresh leaves with one
bud and two leaves or one
bud and three leaves and uniform in size; s3, the picked fresh leaves are subjected to withering, fixation and rolling in sequence, and tea leaves are obtained; s4, mixing the tea leaves obtained in the step S3 with brown
sugar, and performing anaerobic
fermentation in a closed environment; and S5, tedding and airing the tea leaves subjected to anaerobic
fermentation to obtain the sour tea. According to the method, the tea leaves and the brown
sugar are mixed and then subjected to anaerobic
fermentation, in the anaerobic fermentation process, the brown
sugar serves as an important
nutrient substance, fermentation substrates are increased, energy is provided for
mass propagation of microorganisms, rapid fermentation of the microorganisms is promoted, effective microbial communities are generated, the
nutritional quality of the sour tea is further improved, and the prepared sour tea has a certain hypoglycemic effect.