Objective To evaluate the effect of preparation process on the bonding strength of the nitrogen-doped TiO2-xNx films on brackets. MethodsRadio frequency magnetron sputtering was used to prepare nitrogen-doped TiO2-xNx films on the surface of stainless steel brackets. Post annealing was performed on TiO2-xNx films at 450℃ in nitrogen atmosphere for 2 h. The structures and surface morphologies of 3 types brackets, ordinary stainless steel brackets, nitrogen-doped TiO2-xNx films on brackets before annealing and the brackets after annealing, were evaluated by X-ray diffraction. The base plate of brackets was observed by scanning electron microscopy (SEM). The three types of brackets were also divided into 2 groups according to storing methods: distilled water at room temperature and thermal cycling. Sixty extracted human premolars (due to orthodontic demand) were bonded with 6 kinds of brackets using Jing-Jin enamel adhesive (n=10). All bonded specimens were tested on electronic universal testing machine to determine the bond strength. The data were analyzed by SPSS 17.0 software and the results were analyzed by one-way ANOVA. Results The TiO2-xNx thin films on brackets were in anatase phase, with the grain size being 30 nm. The base plates of 3 brackets were clear and well-organized, with no obvious differences. One-way ANOVA test showed that the bond strength of the brackets was significantly decreased after thermal cycling (P<0.01), and there were no significant differences among the 3 groups with the same storing methods (P>0.05). Conclusion The bonding strength of the nitrogen-doped TiO2-xNx films on brackets is not influenced by the preparation process, and can meet the demand of clinical orthodontic application.