Abstract: The ultrafine In₂O₃ powder was prepared by the Sol-gel method. And the properties of the product were studied.Expemiments show that under the conditions of 1:1 HCl leaching Indium at 60-80℃, NH₃H₂O as precipitating agent, controlling pH5-8 and temperature 50℃, drying the precipitate at 80-100℃, then burning at 850℃,The ultrafine In₂O₃ powder with average particle size 0. 015 um and purity 99. 99% can be obtained. This is a method with uncomplicated equipment and simple flowsheet,little pollution, high quality and good properies of the product.