The product namely Hexa Propylene Glycol Cyclotriphosphazene (HPGCP) was synthesized and its inhibitive performance as corrosion inhibitor towards the corrosion of copper in neutral solution of 3% NaCl has been investigated using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). Polarization curves indicate that HPGCP is a mixed inhibitor, affecting both cathodic and anodic corrosion currents. The inhibition efficiency of HPGCP, which reached 96 %, was observed in 10-3 M concentration. The adsorption of the inhibitor on the copper surface in the 3% NaCl solution was found to obey Langmuir’s adsorption isotherm. The inhibition mechanism was determined by potential of zero charge measurements and some electronic parameters.