The corrosion behavior of an automobile body caused by de-icing salt was classified into various corrosion phenomena, of which paint exfoliation and perforation were studied fundamentally. There are 2 types of paint exfoliation. One is paint adhesion, where underfilm corrosion plays a decisive role. Another is wet adhesion, where water immersion through the paint film into the paint/substrate interface is important. Perforation corrosion can be simulated by corrosion test using lapped panel specimens. CCT conditions which should be applied for all exposure tests were determined on the basis of experimental data.