The invention relates to the technical field of fabric manufacturing, and discloses a method for preparing a mite-preventing fabric. The method comprises the steps that firstly, CaCO3 is adopted as a wall material, mite-preventing medicine is adopted as a core material, and mite-preventing microcapsules covered with CaCO3 are prepared; then mite-preventing finishing liquid is prepared, and contains the mite-preventing microcapsules and a waterborne polyurethane adhesive; finally, a fabric is soaked in the mite-preventing finishing liquid, and the mite-preventing fabric is obtained after drying. The mite-preventing microcapsules prepared from CaCO3 as the wall material are free of toxins and high in strength, the situation that the mite-preventing microcapsules are broken in the finishing process, and consequently the medicine is released and leaked is not prone to happen, and the good medicine slow release effect is achieved. When the mite-preventing finishing liquid is prepared, the waterborne polyurethane adhesive is added, the bonding force of the mite-preventing microcapsules and the fabric is improved, and therefore the mite-preventing durability of the fabric is remarkably improved. The selected mite-preventing medicine has the good mite resisting effect, and is low in toxicity to the human body and small in skin irritation. The method can be widely applied to various fabrics prepared from natural fibers or synthetic fibers.