The invention provides a dynamical system of a hybrid electric vehicle. The system comprises a front shaft drive, a back shaft drive, a battery and a monitoring module, the monitoring module is connected with the front shaft drive, the monitoring module is connected with the battery, and the monitoring module is connected with the back shaft drive, and the battery is connected between the front shaft drive and the back shaft drive; the front shaft drive comprises a first clutch, a second clutch, an engine, a first motor, a first gear, a second gear and a third gear, the first clutch is connected between an output shaft of the engine and a gear shaft of the first gear , the second clutch is connected between an input shaft of a retarder and a gear shaft of the second gear, a motor shaft ofthe first motor is connected with a gear shaft of the third gear, and the battery is connected with the first motor; the first gear is meshed with the second gear, and the second gear is meshed with the third gear. The dynamical system of the hybrid electric vehicle can solve the problem that the structure inside a compartment of a precursor engine is complex in an existing dynamical system of a hybrid electric vehicle.