TiO 2 nanoparticle film catalysts with different thicknesses were prepared by plasma enhanced chemical vapor deposition(PECVD) method and the surfaces were subsequently treated by TiCl 4 or O 2 plasma. Two kinds of TiO 2 films with different surface properties were obtained. Their surface microstructures and energy levels of surface states were tested by AFM, XRD, SPS. The photocatalytic activities of the catalysts were determined via photodegradation experiments of phenol. The results demonstrated that photocatalytic activities of samples whose surface was treated by O 2 plasma were greater than those treated by TiCl 4 plasma. Moreover, photodegradation ratio of phenol during the first hour catalyzed by 0.17 μm thickness TiO 2 nanoparticle film was greater than other samples. Especially, the difference of photocatalytic activities of TiO 2 nanoparticle films treated by TiCl 4 or O 2 plasma was respectively explained by energy band theory. TiO 2 nanoparticle film catalysts with different thicknesses were prepared by plasma enhanced chemical vapor deposition (PECVD) method and the surfaces were subsequently treated by TiCl 4 or O 2 plasma. Two kinds of TiO 2 films with different surface properties were obtained. and energy levels of surface states were tested by AFM, XRD, SPS. The photocatalytic activities of the tires were determined via photodegradation experiments of phenol. The results herein that photocatalytic activities of samples whose surface was treated by O 2 plasma were greater than those treated especially, the difference of photocatalytic activities of TiO 2 nanoparticle films treated by TiCl 4 or O 2 plasma was respectively explained by energy band theory.