Titanium oxide thin films were deposited by DC reactive magnetron sputtering(RMS) with Ar ion-beam assistance using end-Hall ion source at low oxygen partial pressure and long target-to-substrate distance. The optical and structural properties of deposited films were investigated by the measurement of measured transmittance and reflectance, atomic force microscope(AFM), and X-ray diffraction(XRD). The results show that the Ax ion-beam assisted RMS for titanium oxide thin films induces the higher packing density, lower absorption, and smoother surface than the conventional RMS, suggesting that it can be employed in deposition of optical dielectric coatings.