Abstract: Corrosion-resisting and heat-resisting coatings of 18-8 stainless steel were made by arc spraying, aluminizing and diffusion treatment on cast iron.The microstructures and chemical compositions of coatings with aluminizing and diffusion treatment were studied by optical microscope, scanning electron microscope and Xray diffraction.And the adhesive strength of coatings was evaluated by thermal fatigue tests.The results show that there is some regions with metallurgy bonding on the interface between coatings and substrates through aluminizing and diffusion treatment, therefore, the adhesive strength of coatings were improved greatly.And a long period of aluminizing time is adverse to the adhesive strength of coatings, so aluminizing time should be controlled well.