Abstract: Corrosion of aluminum tube in SCAL (Surface Condenser Aluminum Exchangers) indirect air cooler system could cause the leakage of circulating water, which will affect the stable and safe operation of thermal power plant. In order to slow down the corrosion rate of materials in the system, demineralized water was used as circulating water, but the corrosion products of carbon steel pipelines would pollute the circulating water quality,and the influence of these corrosion products on the corrosion of aluminum had not been clarified. The problem was studied by means of field coupon test and laboratory simulation tests. The results show that the corrosion products (γ-FeOOH and Fe₃O₄) of some carbon steel would adhere to the surface of the aluminum tube, which would accelerate the corrosion of the aluminum tube.