The present invention discloses soymilk for lowing blood glucose and a preparation method thereof. The soymilk is characterized in that the soymilk is made from the following raw materials in parts by weight: soybeans 400-450 parts, soybean meal 50-60 parts, garlic 12-14 parts, balsam pear 14-15 parts, wheat germ powder 8-9 parts, semen coicis 20-22 parts, cortex lycii radicis 4-5 parts, rhizoma anemarrhenae 2-3 parts, milkvetch root 2-3 parts, root bark of white mulberry 4-5 parts and flour 40-45 parts. The soymilk uses the soybean meal to replace part of the soybeans so that production costs can be reduced; through adding water into the soybean meal and then carrying out magnetic stirring, protein can be fully dissolved; and the soybeans are fermented before grinding, which not only improves nutritional value, but also gives a unique taste of the soymilk. Furthermore, the soymilk is pure and fresh in taste with the addition of vegetables, and also has an effect on lowing blood glucose with the collocation of Chinese medicinal herbs.