The invention relates to low-GI biscuits as well as a preparation method and application thereof, and belongs to the field of foods. The biscuits comprise the following raw materials of flour, maltitol, edible oil, a modifier, flavored raw materials, resistant dextrin containing soluble dietary fibers and being low in GI value, konjaku flour, celery powder containing insoluble dietary fibers and being low in GI value, tartarian buckwheat powder, soybean powder, green bean powder, wheat fiber powder and buckwheat powder or black rice powder. The preparation method of the low-GI biscuits comprises the following steps of mixing the green bean powder with the soybean powder to obtain a first mixture; enabling the maltitol and the modifier to dissolve to obtain a second mixture; and then mixingall of the raw materials, performing stirring, performing curing, performing calendering, performing shaping and performing baking. The method is simple and easy to operate, and large-scale production can be realized. The made biscuits are balanced in nutrients and high in content of dietary fibers, have low GI value, and are rich in fragrance and loose in mouth feel. The biscuits are suitable for being eaten by patients needing to control the blood sugar, the peak of the blood sugar of the patients after the meal can be effectively controlled, and besides, the biscuits are strong in satiation, and can achieve the effect of controlling the body weight.