A synergistic fungicide composition and a preparation method and a use thereof. The composition comprises two active ingredients A and B, wherein the active ingredient A is benziothiazolinone, the active ingredient B is selected from one of dithianon, dimethomorph, iprodione or epoxiconazole, and the weight ratio of the two ingredients is 1:50-50:1, preferably 1:30-30:1. Experiment results show that the fungicide composition has a significant synergistic effect, and more importantly, it needs less application amount and reduces the cost in use. The fungicide composition is effective in preventing and treating certain fungal diseases of crops such as food crops, vegetables, and fruits.
