Health degradation by corrosion of steel in civil engineering, especially in rough environment, is a persistent problem. Environment pollution and global warming will exacerbate this problem. The assessment of whole-life costing and residual service life prediction of structures is very important. Pitting corrosion is the most important factor which influences the service life of the reinforced concrete structures in many chloride included environments. Electrochemical impedance spectroscopy (EIS) method is used to study the corrosion process of reinforcing steel in cement mortar. According to the results of the experiments, dispersion and diffusing effect control the electrochemical process of carbon steel corrosion in the cement mortar. By fitting the results with EC, the parameters about CPE and Warburg impedance are calculated. The pitting corrosion behavior of reinforcing steel in cement mortar has been studied by electrochemical noise analysis (ENA) method, the wavelet transform has been employed to analyze the EN data of reinforcing steel in mortar, and the energy distribution plot (EDP) is plotted. The experimental results show that the change of EDP during the corrosion process can qualitatively reveal useful information on corrosion mechanisms. (C) 2007 Elsevier Ltd. All rights reserved.