Abstract: Corrosion product was prepared by sifting out and eroding crushed ITO target powders with aqua regia. Morphologies, structures and components of corrosion products of foreign targets of target-A, target-B and target-C were studied by SEM, TEM and XRD.Resultsshowed that the products were second-phase; the second-phase of target-A was approximate equiaxed, which was considered as In₄Sn₃O₁₂ and the second-phase of target-B and target-C contain both approximate isometric In₄Sn₃O₁₂ and narrow slice In₂SnO₅; the amount of second-phase of target-A was 8.32% more than that of target-B and 4.48% that of target-C.