In(OH)3 and InOOH were prepared through a simple hydrothermal method at different volume ratios of En and H2O. C-In2O3 and H-In2O3 were obtained by annealing these two precursors at 400°C in air, respectively. One-step In2O3 was also synthesized via solvothermal process using DEG as solvents. The effects of reaction conditions on phase structures and morphologies were studied. The gas sensing properties of the obtained materials toward ethanol were measured and X-ray diffraction, field-emission scanning electron microscope and PL were used to characterize the as-obtained products.