Abstract: A method for the determination of Fe, Ca, Mg, Al, Si in In₂O₃-SnO₂ sintered mix powder with alkali-melt, using hydrochloric acid acidification after immersed in hot water, by inductively coupled plasma atomic emission spectrometry (ICP-AES) is developed. The results showed that after the addition 0.80 g of sodium hydroxide, 0.500 0 g of the sample and fused for 120 min in an ashing furnace, the sample can be completely dissolved. The effects of matrix indium and tin can be eliminated by the matrix matching method, and no spectral interferences between the measured elements took place. Sodium salt has a certain influence on the determination of silicon, which can be eliminated by the addition of a certain amount of sodium hydroxide in standard solutions. Standard spiking test and precision were carried out. The relative standard deviations(RSD)were less than 5% and the recoveries were 90%~105%.