The microstructural and luminescent properties of sputtered GaN thin films pre-irradiated and the (gamma) -ray irradiated were systematically investigated. Analytical results revealed that the increasing dose of (gamma) -rays could enhance the more occurrence of nitrogen vacancies which not only created a prominent deep level luminescence but also destroyed the crystallinity of GaN thin films. For lose dose of (gamma) -ray irradiation (4 Mrad (GaN)), evidence showed that by raising the irradiation dose, more associated Ga-H complexes will be effectively promoted, yielding an enhanced yellow bad emission. However for high dose of (gamma) -ray irradiation (4 Mrad (GaN)), further higher dose of (gamma) - rays could lead the dissociation of Ga-H complexes in GaN samples, resulting in a repressed yellow band emission.