Hot deformation characteristics of molybdenum was investigated by hot compression tests carried out in the temperature range of 900-1450 °C and strain rate range of 0.01-10 s-1. A constitutive equation of hot deformation of molybdenum based on the flow stress was established. With consideration of the effects of the deformation temperatures and the stain rates on microstructures and properties of molybdenum, processing maps were established based on the dynamic material model (DMM). And the instability zones of flow behavior could also be recognized by the maps. The hot deformation characteristics of molybdenum in different zones were also analyzed.