To overcome the limitations of conventional constant-speed control methods in extreme mountainous conditions, this paper proposes a variable-speed coordinated longitudinal-lateral control strategy based on the coupling characteristics of vehicle dynamics. The strategy adopts a hierarchical control structure. The upper layer develops a steady-state evaluation model to provide decision support for subsequent control layers. The middle layer primarily utilizes a two-level model predictive control (MPC) framework to coordinate potential conflicts among longitudinal four-wheel slip rates, lateral active front steering (AFS) and direct yaw control (DYC), and outputs the total driving torque and yaw moment. The lower layer employs a weighted least squares method to optimally distribute torque based on the vehicle’s operating state. A simulation model is constructed using Simulink and CarSim to evaluate performance under various complex road conditions. Results demonstrate that the proposed strategy significantly improves the driving stability of distributed electric vehicles under variable-speed extreme conditions.