Aiming at the performance-limiting characteristics of short hole diffusion length (2-4 nm) and sluggish water oxidation kinetics in hematite (α-Fe₂O₃), we developed hematite nanobelts containing ordered oxygen vacancies by catalyzed oxidation of palladium nanocrystals for efficient photoelectrochemical (PEC) water splitting. Morphologies and structures of as-prepared films were characterized by different methods. Results show that ordered oxygen vacancies was observed in hematite nanobelts with a periodicity of 1.48 nm corresponding to ten times of (11ˉ2) interplanar spacing. The PEC performance of the hematite nanobelts exhibits stable photocurrent density of 3.3 mA·cm^-2, the corresponding hydrogen evolution rate of 29.46 μmol·cm^-2·h^-1, and an early onset potential of 0.587 V (vs. RHE) without additional oxygen evolution reaction cocatalysts. The enhanced performance can be attributed to the introduced ordered oxygen vacancies which can increase the carrier density, greatly accelerate the surface holes transfer, and act as surface active sites to significantly promote the surface water oxidation reaction.