The corrosion inhibition property of a hydrazone derivative, namely 2-(2-{[2-(4-pyridylcabonyl)hydrazono]methyl}phenoxy)acetic acid (PMA) for mild steel surface corrosion in synthetic seawater medium was analyzed by weight loss, electrochem. techniques (potentiodynamic polarization and electrochem. impedance).PMA is a good corrosion inhibitor and the inhibition efficiency increased with the increase of PMA concentration, while the adsorption followed the Langmuir isotherm.XPS, SEM, theor. calculation of electronic d., mol. electrostatic potential and mol. dynamics were carried out to establish mechanism of corrosion inhibition for mild steel with PMA in synthetic seawater medium.The inhibition action of the compound was assumed to occur via adsorption on the steel surface through the active centers in the mol.The corrosion inhibition is due to the formation of a chemisorbed film on the steel surface.