The invention relates to a galvanized layer chromium-free passivant and a use method thereof, wherein the passivant comprises a passivation film-forming agent, an adhesion promoter, an emulsifying agent, acetone and an aqueous solution, when using, the chromium-free passivant and water are diluted according to the proportion of 1: 4 and then put in a passivation tank, a galvanized part is bright-dipped through diluted acid at a plating bath outlet of a continuous electrogalvanizing production line, then enters into the passivation tank under the normal temperature for passivating 5-20 seconds, taken out, flushed with water and dried by hot air. The galvanized layer chromium-free passivant forms a passivation film on the metal surface by reasonably utilizing certain chromium-free organic acids, and the like, has corrosion inhibition property, adopts resin as the promoter as well as the acetone and water as solvents, is prepared by adopting a compound method, free of chromium and used for carrying out passivating treatment instead of chromate and chromium trioxide and eliminates hazards to the environment and the human body from chromium pollution.