Abstarct: In this experimental research work we have studied the morphological, structural, optical and electrical properties of pure indium oxide (In2O3) samples grown by spray pyrolysis method. In order to characterize the samples we have used Field effect scanning electron microscopy (FESEM), X-ray diffraction (XRD), UV-Vis-NIR spectroscopy, photoluminescence (PL) and I-V characteristics apparatus. Through this study we have used indium chloride (99.99% purity) as the source material for the spray solvent. The variable parameters in this research are as following: substrate temperature (350 - 450 oC) and annealing, the spray rate (1.7, 3.3 and 4.8 ml/min) and annealing, substrate type (glass, FTO and silicon) and finally the spray method (continuous and pulse). The FESEM images of the samples confirm the formation of various nanostructures in the films and the XRD spectra indicate that all the laxyers have a polycrystalline nature before and after annealing. Also the transmission spectra of the samples indicate that all samples have a high transmission (> 70%) in the visible range with a direct optical band gap of about 3.9 eV. The PL spectra of the samples at room temperature are consist of two main peaks, one in the UV region (corresponding to the band to band recombination) and the other in the visible range (corresponding to crystal defects especially oxygen vacancies). The electrical measurements show all the grown laxyers have a relatively high electrical resistance (about mega ohm) that decreases drastically as they exposed to the UV irradiation.