Abstarct: Diluted magnetic semiconductors (DMS) are materials that simultaneously exhibit ferromagnetic and semiconducting properties. They are common semiconductor materials containing a few atomic percent of transition mextal (TM) ions substituted with the cation sites. Among ferromagnetic III–V semiconductors, the (Ga,TM)N DMS is the most well understood and promising applications in spintronics, since the high Curie temperature of above the room temperature. In this work, the electronic and magnetic properties of pure and doped GaN nanotubes with 3d transition mextal were studied baxsed on spin polarised density functional theory using the generalized gradient approximation (GGA) with SIESTA code. The calculations have been done on armchair (3,3), (5,5), (7,7), (8,8), (9,9), (10,10), (12,12), (14,14) and zigzag (3,0), (5,0), (7,0), (8,0), (9,0), (10,0), (12,0), (14,0) GaN nanotubes. The results revealed the semiconductors properties of this nanotubes. The electronic structures show that both zigzag and armchair GaN nanotubes are semiconductors with direct and indirect band gap respectively, and in both type of nanotubes the value of band gap increases by increasing tube diameter and the trend of band gap changes in zigzag nanotubes is higher than the armchair nanotubes, but this trend slowdown in higher diameter. The symmetry of density of states indicate lake of magnetic properties of pure nanotubes. Armchair (3,3), (5,5) and zigzag (5,0), (9,0) GaN nanotubes were doped with transition mextals. The spin polarised density of states calculation showed that transition mextal doped GaNNTs are diluted magnetic semiconductors. Doping with V, Cr and Mn, in all cases lead to a ferromagnetic properties. Mn showed the most stable ferromagnetic phases and localized magnetic moment for both types of nanotubes. Nanotubes doped with Co and Ni have been shown antiferromagnetic properties in the stable phases, but nanotubes doped with Fe depending on the position of dopant show both ferromagnetic and antiferromagnetic phases. The total generated magnetic moment in structure increased from V to Fe in presence of transition mextals and reached to the maximum value in Fe dopant whereas by increasing atomic number, the total magnetic moment reduced from Fe to Ni. Half mextallic behavior with %100 spin polarization were observed in the samples doped with Mn. The unique structure of spin-polarized energy levels is primarily attributed to strong hybridization of 3d transition mextal and its nearest-neighbor N-2p orbitals. The calculated transition mextal local magnetic moments and total magnetic moments are compatible with the experimental results. The results of our research can be useful for the experiment upon diluted magnetic semiconductors (DMSs) and systemic investigation in 3d transitional mextals. We suggest that doped GaN nanotubes by transition mextals would have application potential as a spin polarised electron source for spintronic devices in the future.