The invention relates to a preparing method of a nano-rod-shaped indium oxide (In2O3) gas-sensitive material, and belongs to the technical field of preparation of inorganic nanometer functional materials. The preparing method comprises the steps of with indium(III) chloride tetrahydrate being an indium source, by adopting hexadecyl trimethyl ammonium bromide as surface active agent, conducting a hydrothermal reaction under the alkaline condition of sodium hydroxide to prepare indium hydroxide and finally, conducting thermal roasting to obtain the indium oxide gas-sensitive material of a nano-rod-shaped structure. Finally prepared indium oxide is In2O3 with the cubic phase and of the nano-rod-shaped structure, has very good performance of sensing and detecting both nitrogen dioxide gas andhydrogen sulfide gas and is insensitive to other gases (carbon monoxide, ethyl alcohol, ammonia, hydrogen, formaldehyde and the like); the indium oxide also has low working temperature, a quick response and restoration, very high sensitivity, a low detection limit, high selectivity and high stability. Besides, the indium oxide gas-sensitive material can also be used in the fields of catalyst, battery materials, photoelectric materials and the like.