In regards to the flash rusting problem on the cast iron substrates when paintedwith air-drying waterborne corrosion protective coatings，the flash rusting principle was ana. lyzed and the effects of film forming resins，reactive anti-rust pigments and the major function.al additives and film thickiness on the corrosion protective performance of the coatings werestudied and analyzed. The results showed that it was possible to avoid the flash rusting by useof fast-drying water-solubleresin or water-based epoxy resin，nonionic and phosphate ester dispersants and cosolvents，or by control of the film thickness to speed up the touch dry，reduc. ing introduction of ions. The cast iron workpieces could be effectively passivated if ordinaryzinc phosphate and organic heterocyclic compound AR01 were added as antirust pigment，the pH of paint system was adjusted to 9~9. 5，as well as the organic zinc chelate FA-179 was add.ed as anti-flash rusting agent. And the anti-flash rusting properties of the waterborne coatingsystem was improved.