The invention relates to a preparation method of tea yoghourt, belonging to the technical field of food processing. According to the formula, the tea yoghourt comprises the following ingredients by weight ratio: 0.5-1 part of ultrafine green tea powder, 4-8 parts of inoculum concentrations, 9-15 parts of skim milk powder, 4-8 parts of white granulated sugar, and 0.1-0.5 part of a stabilizer, wherein the stabilizer comprises 0.05%-0.1% of xanthan gum, 0.05%-0.2% of CMC-Na, and 0.05%-0.15% of sodium alginate. The preparation method comprises the specific steps of mixing and blending the ingredients in ratio, stirring uniformly, subpackaging, sterilizing, then rapidly cooling to about 42 DEG C, inoculating a leavening agent, putting the inoculated feed liquid into an electric heating constant-temperature incubator being 42 DEG C, fermenting, taking the fermented feed liquid when the acidity reaches 70-80 acid degrees, putting the feed liquid into a refrigerator being 0-4 DEG C, and carrying out cold storage for 17h, thus obtaining finished tea yoghourt product. The tea yoghourt prepared by the method not only can keep the original nutritive value and health of yoghourt, but also has the flavor of tea leaves.