As people’s diet structure changes in modern society, diabetes and its complications have become a global public health concern. China has the world’s largest number of diabetics. Modern science has proved that tea is an important source of natural hypoglycemic polyphenols and plays an important role in the dietary treatment of diabetes as a healthy drink. Tea catechins are the key functional substances in tea, which can effectively regulate blood glucose levels through various pathways, such as inhibiting exogenous carbohydrate hydrolysis, regulating glucose transfer, promoting oxidative decomposition of glucose, inhibiting gluconeogenesis, regulating glycogen synthesis and decomposition, promoting insulin secretion, rescuing insulin resistance and reducing oxidative stress status. Beginning with a summary of recent studies on the effects of tea catechins on obesity, diabetes and metabolic syndromes, this paper moves on to review the latest knowledge on the physiological mechanism of blood glucose stabilization by tea catechins, hoping to provide a theoretical basis for the precise development and application of tea catechins.