The present invention discloses a high-yield corn seed coating agent, which is characterized in that the raw materials comprise, by weight, 5-7 parts of brassinolide, 13-15 parts of a filler, 4-6 parts of gibberellin, 3-5 parts of 6-benzylaminopurine, 0.3-0.5 part of a plant growth regulator, 4-6 parts of salicylic acid, 12-14 parts of oligosaccharin, 3-6 parts of a film forming agent, 0.8-1.2 parts of a binder, 0.4-0.6 part of gamma-polyglutamic acid, 0.06-0.08 part of polyoxyethelene alkyl ether, 0.3-0.5 part of thiophanate-methyl, and 0.2-0.4 part of imidacloprid. The high-yield corn seed coating agent of the present invention has characteristics of seed germination promoting, seedling growth and development promoting, corn seed growth rate increasing, good film-forming function, good slow release function, good biocompatibility with crops, seedling quality improving, pesticide efficacy increasing, strong erosion resistance, effective plant disease and insect pest incidence rate reducing, maintenance cost reducing, and seed germination rate improving, and can slowly release the effective components during the seed germination process.