Abstract: In order to investigate the microstructure and properties changes due to helium irradiation, anatase TiO₂ film specimens were irradiated with helium ions. Irradiation damage was simulated by SRIM program. For researching the phase changes, the crystalline, the structure and morphology, and the electronic resistance and reflectance of Anatase TiO₂ films before and after helium irradiation, specimens were measured by X-ray diffraction（XRD）, Raman spectroscopy（RM）, field emission scanning electron microscopy（SEM）, atomic force microscope（AFM）, four-probe resistivity tester（FPPT） and ultraviolet-visible spectrophotometer（UV）, respectively. The results show that there is no conspicuous phase change after irradiation; crystalline and electronic resistivity is modified clearly; columnar structure is removed gradually; when the irradiation dose is constant, the smaller the ion energy is, the greater the surface roughness and the light reflectivity are; the greater dose results in the smaller light reflectivity when the energy of irradiation ions is constant.