The invention provides a ginseng dietary fiber puffed food and a preparation method thereof, and belongs to the technical field of food processing. The method comprises the steps of firstly, preparation of ginseng dietary fiber powder, wherein specifically, ginseng residues are taken as a raw material, rinsed completely, put in a constant-temperature drying oven for stoving, smashed by a smasher after being stoved and screened, and the screened ginseng residue powder and water are mixed to obtain a mixed solution; soaking is conducted, the mixed solution is centrifuged, a precipitate is collected and stoved, and the ginseng dietary fiber powder is obtained; secondly, preparation of the ginseng dietary fiber puffed food. The obtained puffed food is smooth in surface, uniform in color and lustre distribution, integral in shape, fluffy and crispy in taste, delicate, proper in flavor and puffy, does not stick to teeth and has a specific fragrance of ginseng dietary fibers. It is proved through research that the puffed food further has an effect of reducing blood glucose.