The invention relates to a bactericidal composition comprising the effective components of fenoxanil (A) and one of triazole class compounds (B), wherein the triazole class compounds are selected from tebuconazole, difenoconazole, difenoconazole diniconazole, propiconazole, triazolone, triadimenol and the like, the mass proportion of the A to the B is 30:1-1:50, and the rest is auxiliary components which are permitted to be used and can be accepted in pesticide. The bactericidal composition can be prepared into any one medicament form which is suitable for agriculture to use by a known method, and the better medicament form is wettable powder, oil emulsion, suspension agent, moisture dispersive granules, water emulsion and micro-emulsion. After the fenoxanil and any one selected triazole class compound are compounded according to a certain proportion, the bactericidal composition has an obvious synergistic action and is mainly used for preventing and treating rice diseases.