Hematite (ɑ-Fe₂O₃) nanotube arrays with high aspect ratio and well-defined crystalline structures are highly attractive for photoelectrochemical water splitting. However, their design and fabrication remain a great challenge resulted from the poor thermal stability. Herein, we demonstrate that the high-crystalline Fe₂O₃ nanotube arrays with average length of 2 μm and high density of 2.5×10⁷ tubes/cm² could survive extended calcination temperatures up to ∼800 °C without any sintering. Owing to the well-oriented tubular structure, high light absorption and rich surface defects, this Fe₂O₃ nanotube photoanode exhibits a significantly improved PEC activity for water oxidation, and the photocurrent could be achieved up to 1.2 mA cm⁻² at 1.23 V (vs. reversible hydrogen electrode, RHE). The decoration of FeOOH/NiOOH dual-cocatalysts not only caused a negative shift on onset-potential (170 mV), but also increased the photocurrent density up to 2.0 mA cm⁻² (1.23 V_RHE), which is the highest value among the reported hematite nanotube photoanodes.