A product layer will form on the surface of the concrete after it is corroded by sulfuric acid and which will consequently decrease the corrosion rate. To investigate the chemical components and decelerating effect of the corroded concrete surface layer, a series of immersion tests under different control conditions and in different pH value of immersion acid were carried out. The acid consumption curve during the immersion tests was obtained and the morphology， elemental composition and mineral components of corroded concrete surface layer were analyzed by SEM, EDS and XRD tests. The results show that the lost of CaSO4 and the cleanout of the corroded concrete surface layer during the immersion process would significantly impact the chemical components and decelerate effect of the corroded concrete surface layers. In the condition of replacement of immersion sulfuric acid, the chemical products are SiO2 and other residue materials of cement stone after eroding. In those non replacement cases, the chemical products contain gypsum. Both types of corroded concrete surface layers can decrease the corrosion rate and the corroded concrete surface layer containing gypsum can decrease greatly. The corroded concrete surface layer with gypsum are the main factor that destroys the similarity between different experiments.