Spontaneous electrochemical noise (EN) can be a rich source of information conc-ing the processes simultaneously occurring at a corroding interface. Potential noisefluctuations during the free corrosion of pure aluminum in different concentration ofneutral sodium chloride solution are investigated, and the breakdown and restorationof passive metal’s film are studied using potentiodynamic scanning (PDS) measure-ments and electrochemical impedance spectroscopy (EIS) technique. Two capacitanceloops are observed in the Nyquist plots in two kinds of concentration, and the corro-sion process is under activation control at first, then become diffusion control withinthe oxide film and corrosion products of (Al(OH)p-m Cl-m) accumulated on the surfaceof the corroding electrode. It is suggested that the pitting corrosion is much easierto occur for pure aluminum in 7.0wt% than in 2.0wt% NaCl solution, and the highconcentration of chloride ion in solution inhibits the repassivation of a metastable pit.The corrosion rate deterministic step does not involve Cl-.