This study introduces the operating principle of dual mass flywheel(DMF),and establishes the dynamical equations of transmission system based on the theory of forced vibration and vibration reduction.Coupling with empirical parameters,the rotary inertia distribution of DMF and the torsional stiffness design of DMF are also established.The 2nd order torsional vibration natural frequency(8.5Hz)and other main order frequencies of engine under idle speed are proved to be deviated from the excitation frequencies through the modal analysis.The test shows that the resonance appears at around 255r/min under starting condition,which matches well with the simulation.Under idle speed,the engine angular acceleration fluctuation decreases by 83.5# by using DMF.Under driving condition,the angular acceleration of gearbox input shaft is much lower than that of engine,while under driving WOT of 2nd gear condition,the gearbox angular acceleration is only 141rad/s2 compared with 1947rad/s2 of the engine maximum angular acceleration,and the two angular accelerations of the transmission system with CTD,both around 430rad/s2~930rad/s2,have no great difference.The result shows that the method of designing DMF is reliable,providing a new design concept of DMF.