Food nutrition and food safety have been paid more and more attention, so it is important to find new detecting method. ICP-MS is a good method to detect many elements simultaneously with high accuracy, but detecting more than ten elements simultaneously has little been reported, especially in cereal. Contents of forty elements in corn kernel from Beijing were detected by ICP-MS, we conclude that; 19 elements (Li, I, Co, Ni, Mo, Cs, B, Mn, Fe, Cu, Zn, Rb, Sr, Ti, Cd, Sn, Tl, Pb and Cr) in corn can be precisely and accurately determined simultaneously. As, Se, Bi, Th, U, Sb, Al and rare earth elements could not be precisely detected at this condition, probably due to too low concentrations; Corn from Beijing contains many wholesome trace elements, such as Mo, B, Mn, Fe, Cu, Zn, Rb and Sr; but the toxic elements little, so it is safe and not polluted.