The invention belongs to the technical field of food processing, and particularly relates to a coffee milk beverage and a preparation method thereof. The coffee milk beverage disclosed by the invention is mainly prepared from a coffee extracting solution, a stabilizing agent, a thickening agent, sodium citrate, ethyl butyrate, ethyl maltol, white granulated sugar and water. The coffee milk beverage provided by the invention can effectively solve the problem that the coffee milk beverage is liable to be subjected to fat separation in the storage process to form a cheese circle, the phenomena of oil-water separation, floating and sinking, and protein precipitation are avoided, and the appearance quality of the coffee milk beverage is improved; moreover, the milk flavor and coffee flavor of the coffee milk beverage are strong, and the coffee milk beverage is uniform in structure, and good in mouth feel; the formed oil circle is easy to disperse after being oscillated for a certain number of times, so that the sensory effect of the coffee milk beverage can be effectively improved; and the coffee milk beverage conforms to the taste of modern people.