The invention discloses a silver discoloring preventive intermediate, a composition and discoloring preventive silver and a preparation method. The intermediate is a mixed solution comprising tetraethoxysilane, boric acid, bismuth nitrate and an organic solvent, wherein the weight ratio of tetraethoxysilane to boric acid to bismuth nitrate is 10-13: 1.5-3: 7-10. The composition is a glass body andcomprises silicon dioxide, diboron trioxide and bismuth trioxide based on the weight ratio of 30-35: 10-15: 50-55. The discoloring preventive silver is synthesized by the following steps: (1) mixingboric acid and tetraethoxysilane organic solutions to obtain a solution A; (2) mixing the solution A and bismuth nitrate to obtain the silver discoloring preventive intermediate; (3) soaking silver inthe silver discoloring preventive intermediate; moving out; and forming an intermediate layer on the surface of silver; and (4) thermally processing the intermediate layer; heating; and then decreasing the temperature to obtain the discoloring preventive silver. With the adoption of the silver discoloring preventive intermediate, the color remaining time of the discoloring preventive silver can be prolonged, and meanwhile, the corrosion resisting effect of the discoloring preventive silver can be improved.