This standard specifies methods for the determination of silicon content in molybdenum powder, molybdenum bar, molybdenum trioxide and ammonium molybdate, applicable in the range of 0.0002% to 0.100%. Inductance-coupled plasma emission Light spectrum (ICP-AES) is used to measure the emission intensity of silicon at specific wavelengths, and the mass fraction of silicon is calculated by working Linear dispersion method. The standard details the preparation of reagents, the use of instruments, and the determination procedures, which are suitable for related chemical analysis and quality control.