The present invention relates to a method for preparing low-fat ice cream which is low in fat content, low calorie and has a remarkably soft texture. Specifically, the present invention relates to a composition for low-fat ice cream, containing 0.1-10 parts by weight of tagatose on the basis of the total composition, a method for preparing low-fat ice cream using the composition, and low-fat ice cream containing tagatose prepared thereby which is low in fat content, low calorie and has a remarkably soft texture.