Abstract: When a heavy-duty liquid tank truck is in the case of emergency obstacle avoidance or turning, the coupling of liquid and vehicle will bring about the rollover risk to the truck. To solve this problem, a liquid sloshing control equation was established according to the theory of potential flow, and the sloshing force and torque were calculated. Then, combined with the rigid model of semi-trailer, the liquid sloshing model was integrated into the whole vehicle model of liquid tank truck. The influences on the stability of the tank truck with the same mass of liquid cargo and solid cargo under the effect of excitation were comparatively analyzed in the operating condition of fishhook. Finally, under the effect of this unsteady state factor, the optimal control strategy was designed and TruckSim/Simulink combined simulation analysis was carried out. It is indicated that the optimal control strategy put forward in this paper increases the robustness of the vehicle and plays a guiding role in enhancing the stability of liquid tank trucks.