In this research, we propose a new simple method to fabricate high-density Fe₂O₃ nanowire arrays for solar water splitting, based on oxidation-assisted stress-induced atomic-diffusion. In the presence of water vapor, surface oxidation was promoted during the heating process. The driving force induced by the stress gradient was enhanced due to the expansion of the oxidation layer. Therefore, Fe₂O₃ nanowire arrays were fabricated at a relative low temperature (350 °C) with a high density (8.66 wire per μm²). Using the nanowire array as the photoanode, a photocurrent density of 0.65 mA cm⁻² at 1.23 V vs. RHE was achieved in a three-electrode system.