The invention relates to a solid beverage having an assisted blood glucose lowering function, and a preparation method thereof, wherein the main function components are three or more than three materials selected from kelp or a kelp extract, potassium alginate (low molecular weight potassium alginate), common yam rhizome or a common yam rhizome extract, Chinese wolfberry or a Chinese wolfberry extract, radix puerariae or a radix puerariae extract, mulberry leaf or a mulberry leaf extract, a polygonatum odoratum extract, a bitter gourd extract, the leaf of cyclocarya paliurus and corn stigma, the auxiliary materials comprise one or more than one materials selected from inulin, resistant dextrin, bean powder, tea powder, pumpkin powder, soybean protein powder, barley leaf powder, oat fiber powder, konjac powder and citrus fiber powder, and the flavoring agent is one or a plurality of materials selected from stevioside, xylitol, fructo oligosaccharide, isomaltitol, sucralose, trehalose, matcha powder, and fruit and vegetable powder. The preparation method comprises: 1, crushing, and screening; 2, weighing; 3, carrying out mixing stirring, or carrying out stirring mixing and granulation; and 4, packaging. The solid beverage of the present invention has advantages of significant blood glucose lowering effect, good safety, and no side effect.