The invention relates to a bacteriocidal composition and an application thereof. The bacteriocidal composition is characterized by comprising Boscalid (A) and at least one (B) selected from the following active components of a triazole bactericide: difenoconazole, propiconazole, tebuconazole, hexaconazole, flutriafol, epoxiconazole, tetraconazole, flusilazole, myclobutanil, cyproconazole, triazolone and diniconazole, wherein the mass ratio of A to B is (1:50)-(50:1). The composition can be applied to preventing and treating diseases of crops such as cereal crops, melons, fruits, vegetables and the like.