Fuente: WIPO "dairy products" The present invention discloses a low-fat fermented dairy product and a preparation method thereof. The method comprises the steps of: (1) mixing and stirring a component A and 0-5% of collagen peptide, performing secondary homogenization, performing sterilization, cooling to get a liquid A; mixing and stirring a component B and 0-5% of collagen peptide, performing secondary homogenization, sterilizing to get a liquid B; wherein the component A and the component B respectively comprises 20-60% of low-fat milk and 0.1-1% of a thickener; the total amount of collagen peptide is 2-5% and the molecular weight is 2000-6000 daltons; and total amount of low-fat milk is 70-95%; (2) inoculating fermentation bacteria in the liquid A, keeping warm for fermentation, and cooling; and (3) mixing and stirring a fermented milk base material and the liquid B, and performing sterile secondary homogenization. The invention also discloses application of collagen peptide in a low-fat fermented dairy product. The low-fat fermented dairy product of the present invention is beneficial to bone health and beauty, good in taste, moderate in viscosity, and suitable for daily diet and long-term consumption of general population of all ages.