A virtual prototype of the moving beam balancing system of a heavy-duty hydraulic press working under die forging function is built with Adams, AMESim and Simulink, and the balancing control process is analyzed using this prototype. The moving beam of the heavy-duty hydraulic press may tilt due to the eccentric load during the die forging processing, and thus affect the forging quality and the safety of the press. So it is necessary to research the beam balancing control process. Compared to the traditional methods based on simplified mathematical models, virtual prototype technology can obtain a co-simulation model, avoid tedious formula derivation and solving work, and save test time and cost. Based on the analysis of the working principle of balancing system, this paper establishes a dynamical model of the moving beam, a hydraulic circuit model of the single balancing system and a controller model using Adams, AMESim and Simulink, respectively. Then a virtual prototype is built using the three models via co-simulation interface files. The eccentric load signal is constructed in AMESim according to the variation of eccentric load during die forging process. By adjusting the controller parameters, the rapid balancing of the moving beam under eccentric load conditions is realized, and high precision of dynamic balancing and steady equilibrium is obtained. The simulation results show that the single balancing unit can achieve effective balancing of the moving beam, and the co-simulation analysis method based on the virtual prototype built with Adams, AMESim and Simulink is feasible in the research of the synchronous rectification of the moving beam. This work is a useful exploration in the research of synchronous rectification of moving beams.