The electrochemical corrosion behavior of CP-Ti in nitric acid solution containing fluoride ions was studied by electrochemical measurements including open circuit potential( OCP),potentiodynamic polarization curves( PPC)and electrochemical impedance spectroscopy( EIS). The results show that the corrosion resistance of CP-Ti decreases with the increase of fluoride ion concentration,and the critical value of fluoride ion concentration affecting the corrosion resistance of CP-Ti is 1. 25 mmol/L. The reaction between fluoride ion and protective oxide film on CP-Ti surface results in the dissolution of homogeneous and dense oxide film into porous film,which deteriorates the corrosion resistance of CP-Ti.