To address the yaw instability of the Electric Tracked Vehicle (ETV) in port coal stockpile yards caused by loose and uneven road surfaces, this paper proposes a yaw stability control method based on sliding mode variable structure control. Firstly, a simplified ground shear dynamics model and a vehicle dynamics model are established, which reduced computational complexity while preserving key dynamic characteristics. Simulation results verify the accuracy of the established models. On this basis, a sliding mode variable structure controller is designed to achieve accurate tracking of the yaw rate. A simulation validation platform is built to verify the yaw stability of the proposed control method. The results demonstrate that the proposed controller can effectively suppress yaw instability under conditions such as sudden unilateral resistance changes, thereby maintaining the vehicle's steering and driving stability. This research can provide a methodological reference for the stability control of ETV when driving in coal stockpile yards.