Abstract: The main minerals in molybdenum ores are molybdenite (MoS₂), powellite , ferrimolybdite (Fe₂O₃·3MoO₃·7H₂O), molybdite (MoO₃)and wulfenite (PbMoO₄). Samples were fused by alkali mixture and the total molybdenum in the sample was determined by sulfocyanide colorimetry. Molybdenum in mineral phases of molybdite, powellite, wulfenite and ferrimolybdite was extracted by ammonium hydroxide, tartaric acid, sodium carbonite and hydrochloric acid, respectively and then determined by ICP-MS. Five molybdenum mineral phases in six kinds of molybdenum ores were analyzed and the results were in accordance with the geological facts.