The invention relates to a sterilizing composition. Effective components of the sterilizing composition include penconazole (A) and a methoxyl acrylates bacteriostat (B) which is kresoxim-methyl, azoxystrobin, pyraclostrobin, metominostrobin, trifloxystrobin, picoxystrobin, picoxystrobin, fluoxastrobin, enestroburin, kresoxim-phenmethyl or SYP, wherein the mass ratio of A and B is 50:1-1:50. The mixing of A and B has obvious synergistic function and is used for preventing and killing diseases of fruit trees, cotton, wheat, rice, colza, vegetables, flowers and other plants, particularly for preventing and killing fungoid diseases.