The GaOOH Nanocrystal rods were successfully synthesized by microwavehydrothermal method using Ga2O3 ,HNO3 and NH3·H2O as raw materials. Simple heat treatment of GaOOH in the flow of NH3 gas leads to the formation of submicron GaN rods even at 800°C through GaOOH. The resultant GaOOH and GaN nanomaterials were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The growth mechanism of GaOOH and GaN was proposed. The results indicate that the as synthesized GaN were hexagonal nanorods with average aspects ratio of 5:1(diameter 800 nm and length about 4μm). Photoluminescence spectrum shows that a blue emission peak originates at 473.5 nm, indicating that the GaN nanorods displayed luminescence emission in the blue-violet region, which was related to crystal defects, and may be helpful for electro-optical applications of GaN material.