The inhibitory action of alkaloids extract from Peganum harkmala (AEPH) on the corrosion of 6063 aluminium alloy in 1 M HCl solution has been investigated by weight loss and potentiodynamic polarization technique. The efficiency was found to increase with increasing concentration of the plant extract. The results obtained showed the extract solution of the plant could serve as an effective inhibitor for the corrosion of 6063 aluminium alloy in hydrochloric acid solution. 91.78% is the maximum inhibition efficiency obtained from potentiodynamic polarization technique with 25mg/l of the alkaloids extract at 25°C. The effect of temperature on the corrosion behavior of 6063 aluminum alloy in 1 M HCl with and without addition of alkaloid extract (AEPH) was studied in the temperature range 298–313K by weight loss technique. The adsorption process follows Langmuir adsorption isotherm.