The invention provides a method for preparing an inorganic-organic composite 
passivation solution. The method comprises the steps that nanosilicon dioxide is firstly added into water, 
polyvinyl chloride, 
citric acid and 
sodium bicarbonate are added, temperature is raised, a 
hydrochloric acid aqueous solution is added dropwise, stirring is carried out, the temperature is reduced to 
room temperature, filtering is carried out, and modified nanosilicon dioxide is obtained; then titanyl 
sulfate and 
sodium vanadate are added into H2O2, dispersing is carried out, and a complexing solution is obtained; then 
sodium molybdate is added into water, pH is adjusted to be neutral, the modified nanosilicon dioxide, 
accelerant and a film-forming agent are added, and an inorganic salt 
passivation solution is obtained; and finally a 
silane coupling agent KH570 and a 
silane coupling agent KH858 are added into 
ethanol water, pH is adjusted, the inorganic salt 
passivation solution is added, ultrasonic treatment is carried out, and the inorganic-organic composite passivation solution is obtained. The inorganic-organic composite passivation solution is an environment-friendly product and contains no heavy 
metal ions or volatile organic solvents polluting the environment; the passivation treatment process is simple and low in cost; and the inorganic-organic composite passivation solution can gradually replace a traditional chromate passivation solution, and environment-friendly production of galvanized plate passivation is achieved.