Large-scale In2O3 nanowire (NW) arrays and nanosheet chains are directly integrated on InP substrates via a simple chemical vapor deposition process, benefiting from the substrate-induced, self-assembly and self-catalyzed vapor-liquid-solid growth mechanism. Such particular structures could be expected to have potential applications such as gas sensors and field emission devices. Equally important, remarkable photoinduced wettability conversion between superhydrophobicity and high hydrophilicity has been observed on In2O3 NW arrays. This reversible behavior is ascribed to the photogenerated surface oxygen vacancies and the special nanostructures. Such reversibly switching surface will widen the applications of In2O3 films.