Abstract: The amount of the value elements in the national standard iron ore reference material is small, and there is no effective means of monitoring for determination of other elements, which limits the determination of the elements in iron ore to a certain extent. In this case, effective scientific data couldn’t be provided to support modern exploration geochemistry, which restricts the development of prospecting geochemistry. In this study, the method of determining molybdenum by inductively coupled plasma-mass spectrometry (ICP-MS) was established, and the optimum instrument conditions was investigated. At the same time, it was found that the interference of molybdenum mainly came from the elements of zirconium and iron. The interference degree was different for the different mass molybdenum, so the element of ⁹⁵Mo which has the least interference was chosen as the measurement element. The detection limit of molybdenum was 0.014 μg/g, the recovery rate of the samples was 91%-117%, the precision of the method was 2.06%-5.01%. The method is accurate and reliable, it can provide effective data support for exploration geochemistry.