The height estimation of low-angle target is the core problem of low-angle target tracking. The traditional array super-resolution methods don't have satisfactory performance for low-angle target's height estimation. The performance of the highly deterministic ML method is sensitive to the errors of the reflecting surface height and the reflection coefficient. It is difficult to have prior knowledge of the reflecting surface height and the reflection coefficient. A robust target height estimation method based on low-angle multipath model is proposed in this paper. Making use of the geometric relationship between the direct wave and the multipath waves, one-dimensional ML search is needed for the target height estimation and the computational cost is low compared with the traditional ML method. Echo data-based estimation of the compound reflection coefficient makes the proposed method robust to the errors of the reflection coefficient and the reflecting surface height. Finally, simulation results are presented to verify the effectiveness of the proposed method.