Strict control and accurate measurement of impurity content in high-temperature alloys are particularly important as the trace impurity elements in high-temperature alloys may have a certain impact on the performance of high-temperature alloys．A triple quadrupole inductively coupled plasma tandem mass spectrometry（ICP－MS/MS） was applied to the direct determination of 15 impurity elements in Fe－Ni based superalloys．The sample was firstly digested with a mixture of nitric acid，hydrochloric acid and hydrofluoric acid，then directly determined on the machine after constant volume，without the need for extraction and separation，greatly improving the efficiency of pre-treatment analysis．In the helium collision mode，the testing and analysis of impurity elements with less interference in high-purity iron-nickel based high-temperature alloys were achieved．As ,95,Mo,16,O,+ ,in the superalloy samples with high molybdenum content will cause strong mass spectrum interference to the determination of ,111,Cd，the single quadrupole mass spectrometer test is limited．Based on this，the superior reaction cell technology of ICP－MS/MS was used in this paper to set the mass-to-charge ratio（,m,/,z,） of the primary mass filter（Q1） to 111，and add O,2, to the collision reaction pool，so that ,95,Mo,16,O,+ ,reacted with O,2, to generate ,95,Mo,16,O,16,O,+,，and then setting the ,m,/,z, of the secondary mass filter（Q2） to 111，so that ,111,Cd was passed and detected，thus avoiding the overlapping interference of mass spectra，and stable testing of Cd content was achieved．This study was validated using the iron nickel based high-temperature alloy standard material（GBW01620） as a sample．The results showed that the linear correlation coefficients for each element were greater than 0.999，the detection limits of the method were 0.001－1.24 mg/kg，and the relative standard deviations were not larger than 3.5%．The test values for the 15 elements were all within the uncertainty range of the determined values．This method provides an idea or reference for accurate testing and analysis of high-purity alloy samples.