Abstract: A method for the determination of In in single crystal superalloy containing Ru was established by HR-ICP-MS, and the possible MS interference in the determination of In was studied. MS interference from the ion of Mo oxide to ¹¹³In was very serions; MS interference from the ion of Ru oxide to ¹¹⁵In was found in a certain extent, the amount of interference produced was linearly related to the content of Ru in the sample, which could be eliminated by correction equation. Based on these facts, ¹¹⁵In was selected for detection. 0.1 g of sample was digested with 9 mL of hydrochloric acid and nitric acid with a volume ratio of 3:1 and 1 mL hydrofluoric acid at 80℃ under normal pressure for 60 min, and the digestion solution obtained was diluted to 250 mL with water. HR-ICP-MS was used to determine the content of ¹¹⁵In at three resolution modes, including low resolution of 300, medium resolution of 4 000 and high resolution of 10 000. Standard solution series were prepared by high-purity nickel digestion solution. The mass fractions of In had a linearity relationship with its corresponding response values within 2 μg·g^-1, with detection limits (3s) of 0.002 μg·g^-1 (for low resolution), 0.004 μg·g^-1 (for medium resolution) and 0.009 μg·g^-1 (for high resolution). The standard material (GBW 01636) was analyzed, and the determined values were consisted with the certified values. The sample was used in the spiked recovery test, giving values of recovery in the range of 76.0%-90.0%, and RSDs (n=5) of the determined values were less than 3.0%.