Abstract: In order to understand the basic principle of ultraviolet induced nanoparticle colloid jet machining and efficiently create ultra-smooth surface of brittle crystals, the properties of ultraviolet-visible beam propagation in TiO2 nanoparticle colloid was studied. The ultraviolet-visible beam before and after transmitting through various concentration and absorption layer thickness of TiO2 nanoparticle colloid was measured by an optical power meter. The attenuation characteristics of ultraviolet-visible beam were obtained by measurement experiment based on the theoretical analysis of light absorption and scattering in colloid. Investigation results indicate that, in order to ensure sufficient intensity of ultraviolet light to transmit through TiO2 nanoparticle colloid and irradiate on the work surface in ultraviolet induced nanoparticle colloid jet machining, the colloid concentration should be controlled less than 500 mol/m3, the absorption layer thickness of light-colloid coupling region should not exceed 20 mm.