In order to find the relationship between the salt spray test and atmospheric corrosion, this study used three forms of zinc specimens for salt spray test to determine the experiment period which will achieve the C1 ~ C5 corrosion rating defined by the ISO standard. The experimental results are presented as rulers. The salt spray test shows that the specimen shape and placement are the important factors on corrosion rate. The one-sided exposure specimen with a protective wax coating was placed with the vertical angle of 15 degree. Therefore, the one-sided exposure specimen should be more suitable in the experimental under ASTM B117 conditions.