Gallium oxide (Ga ₂O ₃) nanomaterials have great potential in the fields of ultraviolet transparent electrodes, high-temperature gas sensors, solar blind ultraviolet detectors and power devices, while achieving Ga ₂O ₃nanomaterials with high crystalline quality and controllable size and morphology still remains challenge. Herein, size-controllable Gallium oxide hydroxide (GaOOH) nanorods, nanorod bundles, and spindles were prepared by hydrothermal method. After high temperature calcination, GaOOH nanomaterials were successfully transformed into higher-quality single-crystal β-Ga ₂O ₃nanomaterials which well retained the morphological characteristics of the pristine GaOOH.With the help of X-ray diffraction (XRD), Raman scattering spectroscopy (Raman) and field emission scanning electron microscope (FE-SEM), we systematically studied the influence of the pH value and the concentration of anionic surfactants in the precursor solution on the crystal structure and surface morphology of GaOOH and β-Ga ₂O ₃nanomaterials, and explored the different growth mechanism of GaOOH nanomaterials under different conditions. Simultaneously, room temperature photoluminescence (PL) tests revealed that β-Ga ₂O ₃nanomaterials with different morphologies exhibit typical broad blue-green emission and sharp red emission, which are closely related to the existence of intrinsic defects in nanomaterials.The above research results provide valuable information for the controllable preparation of high-quality β-Ga ₂O ₃nanomaterials.