A mixed-acid modified zinc-cobalt double metal cyanide catalyst, characterized in that the catalyst comprises only the two metal elements of zinc and cobalt, besides impurities; the catalyst is obtained by reacting water-soluble metal salts of zinc and cobalt in water-soluble solvent, and the water-soluble metal salt of cobalt is cobalt cyanide salt; the catalyst is modified by mixed acid during synthesis, the mixed acid comprising at least one organic acid and at least one water-soluble inorganic acid, wherein: the water-soluble inorganic acid is selected from the group consisting of diluted sulfuric acid and diluted hydrochloric acid, with a pH value being in the range of 0 to 5; the organic acid is one or more selected from the group consisting of succinic acid, glutaric acid, phthalic acid, iminodiacetic acid, pyromellitic acid, and 1,2,3,4-butanetetracarboxylic acid; the water-soluble inorganic acid and organic acid being in a molar ratio of 1:10 to 10:1; the step of reacting water-soluble metal salts of zinc and cobalt in water-soluble solvent and the step of modify the catalyst by mixed acid during synthesis are carried out at one or more temperatures ranging from 10 °C to 100 °C; the ratio between the total molar of the water-soluble zinc salt and the water-soluble cobalt salt and the total molar of the mixed acid is 1:10 to 10:1. the catalyst is obtained by reacting water-soluble metal salts of zinc and cobalt in water-soluble solvent, and the water-soluble metal salt of cobalt is cobalt cyanide salt; the catalyst is modified by mixed acid during synthesis, the mixed acid comprising at least one organic acid and at least one water-soluble inorganic acid, wherein: the water-soluble inorganic acid is selected from the group consisting of diluted sulfuric acid and diluted hydrochloric acid, with a pH value being in the range of 0 to 5; the organic acid is one or more selected from the group consisting of succinic acid, glutaric acid, phthalic acid, iminodiacetic acid, pyromellitic acid, and 1,2,3,4-butanetetracarboxylic acid; the water-soluble inorganic acid and organic acid being in a molar ratio of 1:10 to 10:1; the step of reacting water-soluble metal salts of zinc and cobalt in water-soluble solvent and the step of modify the catalyst by mixed acid during synthesis are carried out at one or more temperatures ranging from 10 °C to 100 °C; the ratio between the total molar of the water-soluble zinc salt and the water-soluble cobalt salt and the total molar of the mixed acid is 1:10 to 10:1. the water-soluble inorganic acid is selected from the group consisting of diluted sulfuric acid and diluted hydrochloric acid, with a pH value being in the range of 0 to 5; the organic acid is one or more selected from the group consisting of succinic acid, glutaric acid, phthalic acid, iminodiacetic acid, pyromellitic acid, and 1,2,3,4-butanetetracarboxylic acid; the water-soluble inorganic acid and organic acid being in a molar ratio of 1:10 to 10:1; the step of reacting water-soluble metal salts of zinc and cobalt in water-soluble solvent and the step of modify the catalyst by mixed acid during synthesis are carried out at one or more temperatures ranging from 10 °C to 100 °C; the ratio between the total molar of the water-soluble zinc salt and the water-soluble cobalt salt and the total molar of the mixed acid is 1:10 to 10:1.