The invention discloses a multifunctional bactericidal composition with efficacies of sterilizing, resisting diseases and increasing the yield, and application of the multifunctional bactericidal composition, and belongs to the technical field of pesticides. The bactericidal composition mainly comprises three active components, namely effective amounts of a component A, a component B and a component C, wherein the component A is one of cupric glutamate, copper lysine, copper glycinate and copper disodium ethylenediaminetetraacetate; the component B is one or more of allicin A, ethylicin, polyoxins, validamycin, agricultural antibiotic 120, zhongsheng mycin, astromicin and prochloraz-manganese chloride complex; the component C is an iron-zinc-manganese-molybdenum complex of EDTA; and the composition also can comprise a bordeaux mixture. The bactericidal composition is capable of rapidly and efficiently controlling diseases, promoting crop growth and increasing yield, and has excellent prevention and treatment effects on downy mildew, brown patch, banded sclerotial blight, blight, stem rot, black spot, ring spot, early defoliation, anthracnose and rust disease of field crops.