Porous anodic aluminium oxide (AAO) film is the most widely used template in combination with electrodeposition method to fabricate one-dimensional nanostructures such as nanowires, nanotubes and nanorods. However, the existing oxide barrier layer after the anodization blocks the application of AAO template in synthesis of nanostructures via direct electrodeposition. The thickness and the structure of the barrier layer are the most important factors for nanoarrays electrodeposition.    In order to obtain such nanostructures the barrier layer should be thinned or completely removed. Various barrier layer removal processes were developed: a) thinning process by a successive reduction in DC voltage, or by current-limited anodization steps; b) chemical etching of freestanding AAO membrane in a pore widening solution; c) chemical etching without the need to remove the anodic film from the substrate; d) cathodic polarization of AAO membrane grown on bulk aluminum substrate.  In the present study, we investigated the behavior of the barrier layer in zincate solutions, acidic solutions of cobalt chloride (II) [1,2], as well as in 20% solution of sulfuric acid using as templates pure aluminum and aluminum alloy 1050 [1]. The most promising results were obtain employing freestanding chemical etching and cathodic polarization of AAO membrane in sulfuric acid solution. SEM image of AAO membrane cross-section (alloy AА1050) after chemical etching in solution of sulfuric acid: T = 60°C, t = 9 min. SEM image of AAO membrane cross-section (alloy AA1050) obtained in potentiostatic mode: E= -0.85 V, T = 20°C, t = 70 min.   The results show the possibility of barrier layer thinning and even it practical removal. Treatment of AAO templates in sulfuric solution under potentiostatic mode allows to control the process of thinning by changing temperature, potential and time.   Acknowledgments: This study was founded from Research Council of Lithuania (MIP-031/2014) and Moldavian national project 15.817.02.05A.