HfO2 thin films have been deposited by ion assisted deposition (IAD) with End-Hall and APS ion source respectively. Comprehensive characterization of these films such as transmittance spectra, optical constants, crystal structures, surface topography and absorption (1064 nm) have been studied via Lambda 900 spectrophotometer, variable angle spectroscopic ellipsometry (V-VASE), X-ray diffraction (XRD), scanning electron microscopy (SEM), ZYGO interferometer, and laser calorimeter. The results show that thin film properties have a close relationship with ion source and starting material. The films deposited with End-Hall ion source presents slightly inhomogeneous. These films made with End-Hall and APS ion sources respectively show high refractive index and low absorption loss, and the crystal structures of these films are monoclinic. Under deposition with different ion sources, the films prepared with hafnium as a starting material show even surface, low root mean square roughness and total integrated scattering. Compared with End-Hall ion source, the films deposited with APS ion source show lower absorption.