The invention discloses health-care food for improving bone density and a preparation method thereof. According to the weight of 0.4g of contents in each grain, 1000 grains of capsules are prepared, and each component and the dosage are as follows: 100-200g of functional red yeast rice, 87-200g of milk mineral salt, 3-14g of zinc gluconate, 40-120g of magnesium carbonate, 0.2-0.6g of cupric sulphate, and 0.2-0.6g of vitamin D3. The preparation method comprises the following steps: respectively screening the functional red yeast rice, the milk mineral salt, the zinc gluconate, the magnesium carbonate, the cupric sulphate, the vitamin D3 and auxiliary materials through an 80-mesh sieve, mixing the materials according to a compounding ratio, pelletizing the mixture, drying granules, trimming granules, generally mixing the granule, and then loading the granules into hollow capsules to obtain the health-care food. The health-care food for improving the bone density, disclosed by the invention, solves the problems that calcium loss cannot be restrained by simply enriching the calcium, the calcium utilization rate is low, even hypercalcemia is initiated and the like, and avoids the limitation of the application of similar estrogen components. The health-care food can promote the absorption of the calcium and can improve the deposition of skeleton calcium salt, so that the calcium utilization rate is improved.