The invention belongs to the field of agricultural bactericide and particularly relates to compound bactericide containing benzo alkene triflumizole and tetraconazole. Effective ingredients of the bactericide are benzo alkene triflumizole and tetraconazole, and the weight ratio of benzo alkene triflumizole to tetraconazole is 1:(0.1-10) and preferably 1:(2-3). Bacteriocidal spectrums are expanded by means of the prepared bactericide, and the bactericide has high activity for powdery mildew of various crops; the synergistic effect is obvious and remarkable without simple combination of activity of various components; the prevention and control efficacy of the bactericide is strong, the persistent effect period is long, and resistance risks are small; the amount of effective ingredients used in a field is reduced, production and use cost is reduced, and pesticide residues and environmental pollution are reduced; the compound bactericide is composed of the effective ingredients of different action mechanisms, and therefore is beneficial for overcoming and delaying generation of germ pesticide resistance and safe to crops.