This standard specifies a method for the determination of the content and distribution of trace mg and gallium in aluminum nitride single crystals using secondary ion mass spectrometry (SIMS). This method is suitable for the quantitative determination of mg and gallium content in aluminum nitride single crystals. The determination range is not less than 1 × 10 ^ 16 atoms/cm ³ of elements per cubic centimeter, and the element content (atomic percentage) is not more than 1%. The secondary ions generated by the oxygen Ion source under high vacuum conditions bombard the surface of the sample, sputtering out a variety of particles, and separating and recording the ion count rate with Mass Spectrometer. Quantitative analysis is carried out using the relative Sensitivity factor. This method effectively provides accurate data and distribution information of trace elements in aluminum nitride materials.