Holding the work piece for the forging press is the main task of the forging manipulator, and it is recognized as one of industry’s most arduous tasks. To ensure the safety of the manipulator mechanism, the resistance force exerted on the clamp must be minimized . This paper focuses on the vertical load analysis of lifting systems for the forging manipulator when it works in cooperation with the forging press. First the equivalent stiffness model of the work piece is presented and the loads of the lifting systems are derived. Then the hydraulic circuits of the front and the rear lifting systems are investigated. Finally, the whole forging process is analyzed to study the relationship between the tracking error of the lifting systems and the resistance force on them. Simulation of one typical forging process shows that the cause of resistance force on the lifting system is the displacement tracking error.