Abstarct: Density functional theory provides a suitable tool to study properties of wide range materials with various attributes. Using the Kohn-Sham single particle equations is one of the most important procedures to making the theory applicable. In the first chapter of this thesis, we review the spintronic and their applications in brief. The general and physical properties of the studied materials are mentioned in the second chapter. Chapter three is devoted to density functional theory and its usage in studying the non-magnetic systems. Then we generalized the density functional theory for magnetic systems, and the Kohn-Sham single particle equations would obtained. In chapter 4 and 5 we investigated the magnetic, electronic and structural properties of the materials and compared them with other results. In this study, the wide band gap semiconductors (GaN, AlN) were chosen which doped by different percentage of magnetic atoms such as Cr, Mn and Fe. We used the PWscf code for our calculations in this work which that explained in chapter 4.