<p>As a strong nonlinear system with multi-field coupling, the electric powertrain may result in vehicle vibration under the interaction of internal and external excitation. To improve vehicle NVH performance, the dynamic performance of the electric powertrain should be studied first. However, existing research has limited research on the establishment of an electric powertrain dynamics model. Most studies could not comprehensively consider internal and external excitations and overall electromechanical coupling characteristics. This paper proposed a multi-excitation interaction-based mechatronics model that can be used for electric powertrain to analyze the vibration characteristics. First, the electric powertrain's structure and the mechatronics modeling framework are described. The mechatronics powertrain model is established, including the control subsystem, transmission system, and vehicle dynamics. Next, the influence of internal excitation, such as time-varying meshing stiffness, electromagnetic effect, and static transmission error on the vibration characteristics, is analyzed. The multi-excitation interaction vibration characteristics on the electric powertrain with conditions of variable speed and variable load external excitation are analyzed. Finally, the model verification experiment is conducted. This study can provide an effective reference for the follow-up research on vibration suppression, which is meaningful in improving the durability of electric powertrain.</p>