The characteristics of an anodic oxide film formed by hard anodizing technique were profoundly affected by the processing parameters. The effect of temperature and additive ethylene glycol on the thickness and mechanical hardness of an anodic film formed on AA7075 was investigated. The results showed that the anodic film thickness formed in the sulfuric acid solution increased from 85.52 to 100.25?μm with decreasing the anodizing temperature from 5°C to 0°C. The reason was presumably due to slower mobility of the oxidized species, thus preventing the species from dissolving away to the bulk solution. The lower reaction rate was demonstrated by the lower voltage output in the anodizing curve at 0°C as compared to 5°C. The microhardness test showed that the film formed at 0°C was 13.6 HV harder than that of at 5°C. The additive ethylene glycol enhanced the dissolution rate of the film as indicated by the shift in the voltage output to the positive direction. The film thickness of the anodic film formed in the presence of ethylene glycol varied depending on the temperature. The microhardness of the film dropped significantly to 143.2 and 145.6 HV for 0° and 5°C respectively. The bath temperature controlled the thickness while the additive ethylene glycol affected the hardness of the anodic film.