The invention relates to a making method of a lactic acid bacteria fermented beverage having the function of assisting in reducing blood sugar, and belongs to the technical field of processing of health-care foods. The making method comprises the following steps of uniformly mixing blueberry fruit juice with soybean protein hydrolyzate and bitter gourd juice, regulating the pH to 6.6-7.0, performing sterilization under the condition of 80-85 DEG C for 10 minutes, lowering the temperature to 35-37 DEG C, performing inoculating with 0.01% of lactobacillus plantarum freeze-dried powder, and performing fermentation under the condition of 35-37 DEG C for 20-24 hours, so that lactobacillus plantarum fermentation liquid is obtained; and performing filtering, blending, filling, sealing and sterilizing on the lactobacillus plantarum fermentation liquid, so that finished products are obtained. The lactic acid bacteria fermented beverage not only is rich in fruity flavor and safe to drink, but also has the function of resisting in reducing blood sugar.