Single-crystalline alpha-Fe2O3 nanorods were prepared by a simple and direct hydrothermal method in large quantities. The 1, 2-propanediamine played the role of shape-control agent for the formation of alpha-Fe2O3 nanorods. The characteristics and the evolution mechanism of alpha-Fe2O3 nanorods were investigated in detail. As reaction time prolonged, the hydrogen ions generated by the hydrolysis of Fe3+ could etch the surface of alpha-Fe2O3 nanorods and resulted in the eroded alpha-Fe2O3 nanorods formation. HRTEM results demonstrated that the eroded alpha-Fe2O3 nanorods have rough edges and corners which leading to higher photodegradation ability. Absorption spectra and photocurrent responses indicated that the eroded alpha-Fe2O3 nanorods have a narrow bandgap and higher photocurrent response, which were benefit for absorbing photons and inhibiting the recombination of photogenerated charges. It is expected that the etching of semiconductor materials is an effective way to design the photocatalysts with a high performance, and the alpha-Fe2O3 nanorods with high visible-light photocatalytic activity could find potential applications in the field of environmental management.