Utilization of MSC.Marc FEM software, the typical warm compaction process of molybdeum powder was simulated. Influence of processing parameters of warm compaction on green density of molybdenum powder were studied. Furthermore, the commonly defect existing in green body were analyzed. The results show that compaction pressure is an important factor on green density. At the beginning of warm compaction, average relative density rises linearly along with the increasing pressure. The green density increases with the suppression speed increasing, when velocity value reaches 7mm/s the density will not increase anymore. After the value of friction coefficient is greater than 0.1,green density decreases with the friction coefficient increasing. Influence of temperature on compaction is improvement of the lubrication condition, and reduces the friction coefficient. The appearance of axial tensile stress is the important factor which causes delamination and cracks. Internal friction and lubrication condition of powder mixed system is the important reason results in defect.