The invention discloses a sterilizing composition containing phenamacril. The active components of the sterilizing composition are phenamacril, hymexazol and metalaxyl-M. The sterilizing composition has the advantages that the sterilizing composition is prepared by combing the phenamacril, the hymexazol and the metalaxyl-M, the sterilizing composition is applicable to banana root irrigation treatment and paddy rice seed treatment and capable of effectively preventing and treating banana wilt and paddy rice bakanae disease and damping off, and the use effect of the sterilizing composition is increased; the acting mechanisms of the effective components of the sterilizing composition are different, so that the pesticide tolerance generation of germs can be delayed; by the root irrigation treatment or seed treatment, the number of pathogenic bacteria in soil or seeds can be reduced, and the risks of diseases are lowered; the pathogenic bacterium invasion resistance of bananas and paddy rice are increased, and a large number of pesticides used in conventional prevention and treatment are reduced; the sterilizing composition is efficient, low in toxicity, lasting in effect and quick in action.