With the development of the all-electric land warfare platform, power electronics have increasingly dominated the source-network-load topology for electric tracked vehicles. This paper focuses on the transient characteristics of the source-network-load electrical system for electrically driven tracked vehicles. The time-varying topology, multi-time scale control, strong nonlinearity, weak disturbance rejection, and complex structure of power electronic conversion devices and the vehicle load characteristics are analyzed, and a system model under composite energy supply is established. An average state-space small signal analysis method combined with large signal analysis based on nonlinear decoupling is adopted to analyze the system transient stability. Finally, the effectiveness and accuracy of the established model and the proposed analysis method are verified via simulation. © 2023 Chinese Academy of Sciences. All rights reserved.