The invention discloses a preparation method for reducing hardness of dietary fiber chewable tablets. Dietary fiber chewable tablets are prepared by the procedures of utilizing bamboo shoot dietary fiber powder as main material and carrot, oat, plantain herb, jerusalem artichoke, cassia seed, mannitol, xylitol and calcium gluconate as auxiliary materials, smashing, sieving, mixing, pelleting, drying, tabletting, baking sterilizing, packaging, inspecting and the like. The preparation method is characterized in that on one hand, a gas generating substance (ammonium bicarbonate) is added in the formula, the gas generating substance evaporates in baking sterilizing so that micro gas holes are formed on the chewable tablets, and the chewable tablets become soft and crispy; and on the other hand, large-grained dry carrot added in the formula has low density and certain elasticity, so that the hardness of the chewable tablets is reduced. Dietary fiber chewable tablets prepared according to the preparation method taste smooth, properly soft and sweet and sour, are suitable for middle-aged and elderly people who have bad teeth and need to supplement dietary fibers.