Hot workability of metal molybdenum was investigated by means of hot compression tests carried out in the temperature range of 900~1450 ℃ and strain rate range of 0.01~10 s-1. A constitutive equation of molybdenum for the flow stress was presented. The radial precision forging process of the molybdenum bar was simulated by COGGING modular of FEM software DEFORM. Reasonable process parameters were determined, and the forging penetration efficiency was explored from the strain-effective state. The results show that the forging penetration efficiency criterion put forward for the simulation result analysis is reasonable. Determination methods of the process and parameters are correct. Research shows that the main factors influencing forging penetration efficiency are reduction in pass and the dip angle of the hammer, and the main factors influencing forged piece surface quality are axle feeding speed and rotation angle.