The invention discloses beverage suitable for diabetics to drink and a preparation method thereof. The beverage is characterized in that a formula of the beverage comprises the following main components in percentage by weight: 10%-15% of guava, 10%-15% of carrot, 5%-9% of peanut, 5%-9% of Chinese watermelon, 3%-5% of bitter gourd, 3%-5% of lotus plumule, 3%-5% of cactus, 2%-4% of green tea, 1%-1.5% of royal jelly, 2%-3% of medlar and the balance of water. The preparation method of the beverage comprises the following steps of: picking and weighing materials, cleaning and processing, juicing and filtering, mixing and blending, homogenizing and degassing, sterilizing and filling, inspecting and storing, and the like. The beverage prepared by the preparation method disclosed by the invention has characteristics of being low in heat energy and low in fat, is rich in protein, fat, vitamin A, vitamin B, vitamin C, amino acid, phytosterol, tea polyphenol as well as trace elements such as calcium, phosphor, potassium, iron and magnesium, has medical effect of treating diabetes and lowering blood sugar, can prevent atherosclerosis at the same time, and is convenient to eat and rich in nutrition.