The morphology of indium tin oxide(ITO) nanoparticles was investigated by supercritical anti-solvent(SAS) precipitation method recently proposed to produce size-controlled nanoparticles of various materials in order to enhance productivity and uniformity. From the rigorous performances of the processes, the pressure of 150 bar, the temperature of 50 ℃, the solution concentration of 20%, and the solution feed flowrate of 1.0 ml/min were determined as the best conditions of SAS process parameters used ethanol as a solvent and 9:1 as the solute ratio of indium to tin(In/Sn). Under these conditions, it is confirmed that the particles were obtained about 30 nm with relatively excellent uniformity.