Pump-control-motor hydraulic drive system is a common used volume speed-modulating loop in hydraulic control system. Aiming at the working conditions of the cutter head of the tunnel excavator used in the large underground excavation, a pump-control-motor hydraulic drive system was applied that composed of three variable displacement hydraulic pumps and eight hydraulic motors, which can control the rotate speed of the cutter head in real time. The simulation model of the pump-control-motor was established using the AMESim software. The relationships among the rotate speed, torque of the cutter head and the system pressure, system flow were investigated in detail under several typical working conditions in tunneling. The relevant results can provide theory references for design of pump-control-motor hydraulic control system in other occasions.