Objective To investigate the electrochemical behavior of high-voltage electron aluminum foil in HCl and NaOH solution, and the effect of alkaline or acidic pretreatment on the area-enlarging of electrochemical etching of the aluminum foil. Methods This study compared the pretreatment effect of aluminum foil in different concentrations of HCl and NaOH solution. The electrochemical parameters of aluminum foil in different pretreatment solutions were obtained with polarization curves by which the etching behavior of aluminum foil was analyzed. The morphology observation of aluminum foil surface by means of scanning electron microscope (SEM) was used to analyze the influence of pretreatment on the surface morphology. The morphology and distribution of the pitting etching hole were observed to analyze the effect of pretreatment on the pitting. Results The pretreatment reduced the microstructure inhomogeneity on the foil surface formed during the manufacturing process and improved the surface activity, which increased the pit density and uniformity of pit distribution. The special capacitance of all experimental aluminum foils after electro etching process showed that compared with the primary aluminum foil ( the specific capacitance was 0. 56 μF / cm2 ), the specific capacitance of foil with HCl solution pretreatment increased by 4% ~ 8% ; whereas the specific capacitance of foil with NaOH solution pretreatment increased by about 13% ~ 16% . The self-corrosion potential of aluminum foil in HCl solution was about -820 mV, while the self-corrosion potential in NaOH solution was obviously lower, about -1720 mV. Compared with that in HCl solution, the self-corrosion rate of aluminum foil in NaOH solution was faster. Conclusion The more uniform corrosion in NaOH solution could eliminate the rolling defects of aluminum foil and improve the specific capacitance of aluminum foil.