Renewable energy is spotlighted as a resource to replace fossil fuels, and among the resources, active research on hydrogen energy is ongoing. Various methods have been developed to produce hydrogen energy using photoreduction processes. In this study, we synthesized β-phase iron oxyhydroxide (β-FeOOH) using a hydrothermal method with an optimal synthesis time and investigated its photofunctional properties, including hydrogen production. The obtained samples were characterized and compared with reference data. X-ray powder diffraction results corresponded to the peaks of the reference data. A rod structure was confirmed by scanning electron microscopy, and no impurities were observed. The band-gap energy of β-FeOOH was calculated as 1.8-2.6 eV. A photoreduction process was performed based on a photo-Fenton reaction to produce hydrogen by irradiating ultraviolet (UV) on β-FeOOH. The synthesized β-FeOOH was subjected to UV irradiation for 24 h to produce hydrogen, and we confirmed that hydrogen was successfully produced. The properties of β-FeOOH were evaluated after UV irradiation.