The Er3+-doped Al2O3 optical films have been prepared on thermally oxidized SiO2/Si(100) substrate by the sol-gel method with the dip-coating process, using the aluminium isopropoxide [Al(ОС3Н7)2]-derived Аl2О3 sols with the addition of erbium nitrate [Er(NO3)2·5H2O]. The surface morphology, thickness and structure of the Еr3+-doped Al2O3 films have been analyzed by the scanning electron microscope (SEM), atomic force microscope (AFM), and X-ray diffractometer (XRD). The even, smooth and compact surfaces of Еr3+-doped Al2O3 films were obtained The ciystal size of 50~200 nm was observed for the Er3+-doped Al2O3 films. The thickness of the 1 mol% Er3+-doped Al2O3 film for 9 layers sintered at 900 ℃ is about 1.2 μm under a constant withdrawn rate of 100 mm/min. The phase structure, mixture of γ-Аl2O3 and θ-Аl2О3 was observed for undoped Al2O3 film. The thin film exhibited (110) and (120) preferred orientation for γ-Al2O3 and θ-Αl2O3 phase, respectively. The addition of 1 mol-% Er3+ has slight influence on the phase structure and preferred orientation of Al2O3 film. The photoluminescence (PL) spectra of 0.1 mol-%~1.5 mol% Er3+-doped Al2O3 films were detected at the measurement temperature of 10 Κ The PL peak intensity at 1.533 μm decreased with the increase of the Er3+ doping concentration· The corresponding full width at half maximum decreased from 45 nm to 36 nm.