The effect of some polyethylene glycols (PEG) as inhibitors on the corrosion of aluminum in 1.0 M H₃PO₄ has been studied using weight loss and polarization measurements in various concentrations of PEG and at different temperatures. The dissolution of aluminum in phosphoric acids increases by increasing temperatures and decreases by increasing the additive concentrations. The inhibition efficienciy values proceed according to the following order of the molecular weights of the used inhibitors PEG 4000 > PEG 2000 > PEG 1500 > PEG 400. For relatively higher molecular weights inhibitor (beginning from 1500) the type of adsorption taking place at the surface of aluminum was physical adsorption whereas for the molecular weight. = 400 had different behavior till 50^oC and then the inhibition efficiency decreasing at 60^oC indicating physical adsorptions. The lone pair of electrons of oxygen atom of hydroxyl groups play an important role in the adsorptions of additives on aluminum surface, which affected by polarization. The thermodynamic calculated values of activation and adsorption were calculated and discussed.