Novel hydrazone ligand N-(4-(2-hydrazinyl-2-oxoethoxy) phenyl)-acetamide [HL] and its metal complex of manganese (II) [Mn-HL] were investigated as corrosion inhibitors for mild steel in diluted sulphuric acid solution at 25 + 1oC using three electrochemical methods which show matching in results of three electrochemical techniques; potentiodynamic polarization, cyclic voltammetry & electrochemical impedance spectroscopy techniques. The experimental results clarify the inhibitive effect of N-(4-(2-hydrazinyl-2-oxoethoxy) phenyl) acetamide [HL] and its Mn (II) complex on mild steel that increase in presence of the complex [Mn-HL] more than [HL] where The ligand displayed low efficiencies as corrosion inhibitors against localized corrosion while complex give more efficiency corrosion inhibition. Detailed study effect of 0.1M sulphuic acid with and without ligand and its complex ligand MnCl2 on mild steel shown by Surface morphology of specimen using scanning electron microscope (SEM) and energy dispersive X-ray (EDX) analysis that show improvement appears in surface morphology in surface of mild steel with complex of ligand from localized attack to general attack (homogeneous surface and protective film).