To efficiently create the ultra-smooth surface of brittle crystals, an ultraviolet induced nanoparticle colloid jet machining system was established and the interaction mechanism between the nanoparticles and the surface of a workpiece in the process was investigated. Firstly, the characteristics of TiO2 nanoparticles and monocrystalline silicon surface used in the experiment were measured and investigated. Then, the plane-wave pseudopotential calculation method based on first-principles was used to study the geometrical structures and formation energies of TiO2 molecular cluster in chemically adsorbing on hydroxyl monocrystalline silicon surface. Finally, adsorption experiments of TiO2 nanoparticles and monocrystalline silicon surface were carried out. Calculation results show that the OH is chemically adsorbed on TiO2 cluster and silicon surface, respectively. In the adsorption process between TiO2 nanoparticles and silicon surface, new Ti-O-Si bonds and H2O molecule are formed to reduce the system energy. Infrared spectral experiment results also show that there exits a new generation of Ti-O-Si bond between the interfaces of TiO2 nanoparticles and silicon surface. The new chemical bond between the interfaces satisfies the chemical reaction mechanism in the process of ultraviolet induced nanoparticle colloid jet machining.