Abstract: Molybdenum oxide is an important raw material for steel and chemical industry. The conventional molybdenum oxide producing processes include reverberatory furnace roasting technology, rotary kiln roasting technology, multiple hearth furnace roasting technology, fluidized-bed roasting technology. In these conventional processes, the product quality was low with high concentration of SO₂ (up to 2%) which was hard to be utilized and disposed, and could result in serious environmental pollution. An effective technology of roasting vulcanized molybdenum to produce molybdenum oxide with pure oxygen in the obturation dry condition was introduced, which could reduce the environmental pollution of SO₂ and improve the quality of reaction product. Pure oxygen and molybdenum sulfide were roasted in the obturation dry reactor, with heating temperature less than 650 ℃ in the bottom part, the gas pressure in the reactor less than 0.4 MPa, the oxidizing reaction time between 35 and 50 minutes, and with the highest gas temperature 255 ℃.The results showed that the content of MoO₃ in reaction product reached 93%, higher than that of the reaction product with the common productive technology (80%-85%), and the concentration of SO₂ in flue gas was above 50% (in weight), thus having great practical value for utilization. The experiment proved that the new technology was feasible for MoO₃ and SO₂ recovery.