Nano-ceramic coatings fabricated by high velocity collision process have garnered worldwide attentions due to their realistic applications in diverse fields, such as catalysis, optics and membranes. Inter-particle bonding formation which determining qualities of nano-scale ceramic coatings are influenced by particle collision behaviors during high velocity collision processes. However, the bonding mechanism of nano-scale ceramic particles by high velocity collision is yet to be fully understood. In present study, collision behaviors between nano-scale TiN particles with different diameters, i.e. 5 nm, 10 nm and 15 nm were illuminated by using molecular dyn mic simulation through controlling impact velocity. Results show that nano-scale TiN particles collision exhibits three states, i.e. bonding at low velocities, fracture-rebounding at medium velocities and fracture-bonding at high velocities. Microstructure of bonded particles shows that only those atoms near the compact region displaced from the equilibrium position, atoms far from the compact region were immobility. Microstructures of both fracture-rebounded and fracture-bonded states exhibit obvious fracture at the compact region. These results are summarized into a parameter selection map, providing an overview of the conditions for states of nano-scale TiN particle collision, in terms of particle sizes and velocities. Fracture energy of nano-scale TiN particles is illuminated to understand no isolate fragments of TiN particles by collision, although there exhibit particle factures at impact region. A relationship between the adhesion energy and the rebound energy is proposed to understand bonding formation mechanism for nano-scale TiN particle collision. It can be found that the bonding formation of nano-scale TiN particles at low velocities is mainly attributed to atomic interactions, while the fracture induced by impact is the main reason for particle bonding at high velocities.