The invention relates to the field of food processing, particularly relates to chickpea milk beverage with an alpha-glucosidase inhibiting function and a preparation method of the chickpea milk beverage, and especially relates to research and development of functional foods. The method comprises steps as follows: chickpeas are stir-fried and smashed, obtained flour is mixed with water at the ratio of (1:7)-(1:11) (w/w), the mixture is subjected to gelatinization at the temperature of 75 DEG C-80 DEG C for 35-45 minutes, liquifying enzyme is added for liquification at the temperature of 90 DEG C-95 DEG C for 35-45 minutes, saccharifying enzyme is added for saccharification at the temperature of 60 DEG C-65 DEG C for 8-10 hours, a chickpea milk base material is obtained after filtering, and the chickpea milk beverage is prepared through conditioning, homogenizing and sterilization. According to the chickpea milk beverage and the preparation method, influence of complete chickpeas on alpha-glucosidase inhibitory activity in the gelatinization, liquification and saccharification processes is researched, so that the alpha-glucosidase inhibition ratio of prepared milk is the highest, cane sugar and a stabilizer are added with other conventional methods, and the chickpea milk beverage with excellent functional characteristics can be prepared through processes of homogenizing, sterilization, filling and the like.