Indium oxide (In$_{2}$O$_{3}$) nano spherical crystalline particles have been prepared by hydrothermal technique at 350 $^{\circ}$C, 400 $^{\circ}$C and 450 $^{\circ}$C. The prepared powder was characterized by XRD, SEM, TEM, UV and FTIR spectroscopy. The XRD confirms the spherical indium oxide nano particles were at single crystal phase with BCC and Rhombohedral structures. SEM and TEM indicate the formed In$_{2}$O$_{3}$ nano particles are with diameter 12 nm. These findings should be of importance at both optical and electronic devices as well as theoretical investigations of the concerned crystal structure.