The invention relates to a sterilization combination which contains the effective components of boscalid and bupirimate or ethirimol, wherein the mass proportion of the two effective components is 50:1 to 1:50. After mixing, the boscalid and the bupirimate or the ethirimol have obvious synergism, and are used for preventing and treating powdery mildew of crops such as vegetables, wheats, fruit trees, flowers and the like.