The dual-drive system to be used in the tunnel boring machine (TBM) is a new kind of high-power planetary transmission system. On the basis of the system’s transmission theory and the bond graph principle, the bond graph model of the dual drive transmission system is established and then the state equations are deduced. Based on this model, dynamic performance of the system is simulated by means of MATLAB/Simulink and the dynamic response curves of the speed and torques are acquired. The simulation response illustrates that the bond graph model of dual drive transmission systems is accurate. In addition this system is suitable for three types of TBM and can satisfy the requirements of dramatic changes of load in the running of TBM.