Poly o-phenetidine (POPT) and POPT/TiO2 nanocomposite with different types (Anatase, Rutile, and Mixture of them) and different ratios (0.05, 0.15, 0.20 g) of TiO2 NPs was successfully electropolymerized on 304 stainless steel material by cyclic voltammetry, and Galvanostatic and Potentiostatic technique. The obtained polymers were characterized by FT-IR, UV-vis, TEM, SEM-EDX, and XPS spectra. The anticorrosion properties examined by both of potentiodynamic Tafel polarization and electrochemical spectroscopy. The POPT/TiO2 mixture type with 0.15 g TiO2 NPs showed considerable protection against corrosion in 0.5 M HCl solution compared with the other type and ratio of POPT/TiO2 nanocomposite.