Herein, we presented hierarchical three-dimensional (3D) branched hematite nanorod arrays (NAs) on transparent fluorine-doped tin oxide (FTO) conductive glass substrates, which exhibited high PEC water splitting performance due to the enhancement of mid-visible light harvesting as well as charge separation and transfer. The introduction of a TiO₂ underlayer made the as-prepared 3D branched hematite NAs achieve a photocurrent density of 0.61 mA cm⁻² at 1.23 V vs. reversible hydrogen electrode (RHE) without high-temperature activation.