Disclosed is a method for preparing a glucan beverage, comprising the following steps: (1) inoculating leuconostoc mesenteroides into a fermentation medium, and carrying out aerobic cultivation to obtain a fermentation broth; (2) uniformly mixing the fermentation broth and a blending liquid containing a sweetener and an acidulant, and homogenizing and sterilizing, wherein the fermentation medium contains an aqueous solution of sucrose and tomato juice; the concentration of the tomato juice in the tomato juice aqueous solution is 40%-100% volume percent; the pH of the fermentation medium is adjusted to 6.0-8.0 with a base; and the volume percent of the content of the fermentation broth in the total amount of the glucan beverage is 15.5%-66.6%.
