It is known that SLM (selective laser melting), which belongs to the class of additive manufacturing technologies, enables the rapid and flexible production of complex parts with high precision. However, there is a large variation of the mechanical properties of Ti and Ti alloys. Many factors affect the built part quality, which becomes an important issue in both academic and industrial settings. Therefore, in this study, we focus on the different element compositions in Ti. As it is known that, O, N, H, C and Fe are initially contained in the raw Ti powder as impurities. To the best of our knowledge, these elements show remarkable effects on the microstructures and enhancement of mechanical properties of Ti materials by their solid solution strengthening and grain refinement effect. Two research objectives are addressed in this study. First, a comprehensive analysis of the role played by different N content on selective laser melting (SLM)-processed commercially pure Ti, in terms of the grain structures evolution, crystallographic texture and mechanical properties will be presented. By using the SLM technique, nitrogen shows a powerful effect that is beyond the traditional process. The strength of SLM-processed Ti increased as a function of N content. With N of 0.5 wt.%, it exhibits a remarkably large improvement of tensile strength up to 1200 MPa, which is about three times higher than those of SLM-processed CP-Ti. Besides, superior near-isotropic mechanical properties can be achieved by N addition, while SLM-processed CP-Ti materials were shown to have highly anisotropic characteristics. Later, to raise the ability of yield strength prediction of SLM-processed Ti materials by N solid solution, the theoretical estimation of yield strength will be discussed using the Labusch model and the Hall-Petch relationship.