With soaking treatment, cerium and KH560 silane compound mixture conversion coating are formulated. Various means of analysis such as SEM, EDS, IR, Tafel and EIS were adopted to carry out analysis of surface pattern, element constitution and electrochemical corrosion for mixture conversion coatings of different immersion time. The result shows: When the mixture conversion coating of cerium and silane are formed, the cerium conversion coating takes the priority in generation. Silane conversion coating is mainly absorbed to the cracks of cerium coating, once some exposed base are found at the minor cracks of the silane coating, as a result, definitely cerium coating is generated to make up the exposed base. Therefore, the corrosion resistant capabilities of the mixture conversion coating are higher than pure cerium conversion coating and silane conversion coating.