The invention provides a bactericidal composition comprising active components of fluopicolide and copper calcium sulfate with a weight ratio of 1:100-100:1. According to the invention, fluopicolide and copper calcium sulfate are subjected to binary compounding, such that the composition has a significant synergistic effect in controlling crop diseases caused by fungi and bacteria. With binary compounding, bactericidal spectrum is expanded; the doses of the two components are reduced; and the risk of pathogen drug resistance is reduced.