Abstract: In order to study the interface formation in the growth process of Ti-Si-N films, the first principle calculations were used to investigate the total energies and adsorption energies of 3N-2Ti-1Si, 4N-1Ti-1Si and 4N-2Ti-1Si island configurations on the TiN (001) surface.And the migration activation energies of these islands' configuration evolutions were investigated by nudged elastic band (NEB) method.The calculations results show that the configurations of Ti particle inside the islands are generally stable structures with low energy, which are formed by the separation of SiN phase from TiN phase.Among the configuration evolutions of 3N-2Ti-1Si, 4N-1Ti-1Si and 4N-2Ti-1Si islands, activation energy of 3N-2Ti-1Si island evolution is relative low, and it is easier to realize configuration evolution.With the increasing of the deposition ratio of N particles moderately, the activation energies of configuration evolutions decrease, which promotes the separation of SiN and TiN phase.When the proportion of N and Ti is 3:2, the interface is most likely to form.