Abstract: The sample was prepared with HK 200 sample grinder, and contents of Si, Mn and P in the sample were determined by the direct-reading spectrometer. Influential factors, including matrix effect, position of slit, analytical conditions and method of sample preparation were discussed. Under the optimized experimental condition, values of RSD′s (n=11) of the 3 elements found were less than 5%. The proposed method was applied to analysis of sample of pig iron, and the results obtained were in conformity with those by XRFS and spectrophotometry.