In this article, nanometer-sized In2O3 organosol capped with a layer of anionic surfactants was prepared using microemulsion method. Its structure and optical properties were investigated through transmission electron microscopy, ultraviolet-visible absorption spectra, photoluminescence spectra and Z-scan technique. It was found that the prepared In2O3 organosol showed a series of new optical properties, which can be explained by its special oxygen vacancy structure. These new optical properties enhance its applications in information optics.