The temperature of alumina barrier layer during a high electric field anodization of aluminum (the current density more than 50[Formula: see text]mA/cm[Formula: see text] has been studied by analyzing the aluminum film resistance. In the case of Joule heat power density to be larger than 20[Formula: see text]W/cm2, the temperature inside the barrier layer can exceed [Formula: see text]C, which leads to the local melting of aluminum. Scanning electron microscopy has shown the location of molten aluminum droplets and their movement during the anodization process.