Abstract: The sensitivity factors of Al, Si, Ti, Cr, Mn, Mo relative to Fe are determined using steel standard. One of the standards is measured according to the relative sensitivity factor of elements. It is shown that the satisfactory results are obtained using a same instrument when only the transmitted energy band is fixed and the other experimental conditions not have to eontroll accurately. From the sensitivity factor of elements relative to iron, we can calculate the sensitivity factor of one element relative to another one. Therefore ~ the relative concentration of these elements can be compared.