The invention discloses a calcium carbonate particle composition. The calcium carbonate particle composition is prepared from the following components in parts by weight: 100 parts of calcium carbonate, 3000-4500 parts of powdered sugar, and 120-180 parts of an acid source. The invention further discloses a preparation method of the calcium carbonate particle composition. The preparation method comprises the following steps: weighing calcium carbonate, powdered sugar and the acid source according to the weight parts, taking the powdered sugar, adding purified water into the powdered sugar for preparing the syrup, mixing calcium carbonate and part of the powdered sugar, adding with the syrup, preparing a soft material, carrying out wet granulation, carrying out drying, and carrying out size stabilization, thus obtaining calcium carbonate particles; dissolving the acid source by adopting purified water, after dissolving, adding with the rest powdered sugar, preparing a soft material, carrying out wet granulation, carrying out drying, and carrying out size stabilization, thus obtaining acid particles; and uniformly mixing the calcium carbonate particles and the acid particles. The pH value of the calcium carbonate particle composition prepared by adopting the method provided by the invention is 4.5-6.5, the dissolubility is good, precipitate is seldom generated, the stability is good after the calcium carbonate particle composition is placed for a long term, the problem that the gastrointestinal tract is uncomfortable and can not realize well absorption due to hyperacidity is solved, in addition, the process is simple, the operability is good, and the industrial production as well as popularization and application can be easily realized.