Refractive index and extinction coefficient curves of HfO2, Y2O3, Al2O3 and SiO2 were obtained from their corresponding single-layer thin films. HfO2/SiO2, Y2O3/SiO2 and Al2O3/SiO2 multilayer thin films were deposited by e-beam evaporation. Measurement results show that the experimental reflectances of HfO2/SiO2 and Al2O3/SiO2 agreed very well with the theoretical results, but the experimental result of Y2O3/SiO2 was much lower than the calculated theoretical result which told us that the absorptance performance of Y2O3 relied deeply on the deposition conditions. Deposition environment of Y2O3/SiO2 multilayer may create a large amount of non stoichiometrical Y2O3 which made the absorptance increased abruptly. In addition, absorptances of the fused silica substrate and these multilayer thin films were obtained through calculation.