Abstract: It is presented an investigation of many reinforced concrete columns in four large workshops, since most of the columns are badly corroded.And a discussion of the usage of half-cell technique is carried out to get a fast appraisal of the corrosion state in the concrete structure, and is pointed out the limitation of the identification standard:ASTM C876.Based on the results of this investigation of corrosion damage and finite element method, it is also analyzed this kind of effect when the corrosion of the steel bars occurs in the compressive zone of concrete section of the reinforced concrete column.Even though there are the expanded action of corrosion products, it is clear that the location of stress peak point in the concrete, surrounding the corrosion bar is almost the same.But the compression stress could accelerate the development of corrosion crack obviously, which would speed up the failure of concrete cover.Moreover, corner spalling, and splitting spalling are two more potential models of the concrete cover failure.