In this paper, process of electrochemical dissolution of aluminum electrodes was studied in a solution of sodium chloride at polarization by three-phase alternating current of frequency of 50 Hz. The effect of current density, concentration of sodium chloride and electrolysis time on the current efficiency of aluminum electrodes dissolution was observed. It was established that with rise of current density at the electrodes upto 2000 А/m2 , current efficiency of dissolution increases upto 77.0%, and at high current density, current efficiency of dissolving gradually decreases. With rise of concentration of sodium chloride to 300 g/L, the current efficiency of aluminum dissolution decreases, at concentration of NaCl 100 g/L, (-80.6%) and at NaCl concentration 300 g/L (70.4%). It was established that as the result of the electrolysis dispersed aluminum hydroxide А1(ОН)3 formation is observed, the structure of which was identified by X-ray diffraction and electron microscopy.