TiO2, Al2O3 and SiO2 single layer films were deposited in the oxygen gas atmosphere by plasma assisted e-beam evaporation(PAEBE) at various RF power and low temperature on p-type Si wafer(100) and glasses. The effects of plasma assistance on the optical and microstructual properties of three kinds of single layer films were investigated. In addition, those of the films were compared with the films deposited by conventional e-beam evaporation at high temperature(100similar to 300degreesC) condition. The n-values of TiO2 films gradually increased from 2.405 (lambda=550nm) at 150W RF power to 2.54 at 200W. The XPS result indicated that TiO2 films deposited without plasma assistance have Ti2+, Ti3+ and Ti4+ charge states. Whereas the films prepared at 200W, 250W RF power have only Ti3+ and Ti4+ charge states. Al2O3 layers had maximum reflective index (n=1.604 at lambda=1200nm) at 200W RF power.. but slightly decreased to 1.57 at 400W RF power. The measured transmittance spectra show that all the sample deposited by PAEBE are free from absorption and homogenous as well as the surface roughness, packing density and absorption of TiO2, Al2O3 films improved dramatically compared with films deposited conventional e-beam evaporation. However, The reflective index and surface morphologies of SiO2 films had no changed with increasing RF power.