The driver-automation shared driving is a transition to fully-autonomous driving, in which human driver and vehicular controller cooperatively share the control authority. This paper investigates the shared steering control of semiautonomous vehicles with uncertainty from imprecise parameter. By considering driver’s lane-keeping behaviour on the vehicle system, a driver-automation shared driving model is introduced for control purpose. Based on the interval type-2 (IT2) fuzzy theory, moreover, the driver-automation shared driving model with uncertainty from imprecise parameter is described using an IT2 fuzzy model. After that, the corresponding IT2 fuzzy controller is designed and a direct Lyapunov method is applied to analyze the system stability. In this work, sufficient design conditions in terms of linear matrix inequalities are derived, to guarantee the closed-loop stability of the driver-automation shared control system. Meanwhile, an H ∞ performance is studied to ensure the robustness of the control system. Finally, simulationbased results are provided to demonstrate the performance of the proposed control method. Furthermore, an existing type-1 fuzzy controller is introduced as comparison, to verify the superiority of the proposed IT2 fuzzy controller.