In order to resolve the low Er3+ concentration problem in Er3+ doped Si based light source, the Er2O3 films with high Er3+ concentration and strong 1.535 μm room photoluminescence are fabricated at 900 ℃ on Si(100) and SiO2/Si(100) substrates, respectively, by using the sol-gel spin coating method. Small thermal quenching of 1/5 is observed. PL intensity increases 2~3 times on SiO2/Si substrate compared with that on Si substrate. Er2O3 structure is single cubic. The Er2O3 films with strong PL intensity are promising candidates for application in Si-based light source and amplifier.