Abstract: Landslide monitoring and early warning are essential for geological disaster prevention and mitigation. As an economical monitoring technique,tilt angle measurement shows considerable potential in landslide monitoring and early warning systems. In this study,an indoor landslide model was designed to investigate the effectiveness of surface tilt angle as a monitoring indicator. The variations in surface tilt angle and elevation during the sliding process of the landslide model were analyzed. The results demonstrate that the surface tilt angle can effectively reflect changes in slope stability. Furthermore,it was found that the tangent angle of the tilt curve,after dimension-less processing,can serve as an early warning indicator for landslide failure. The effectiveness of the tangent angle indicator is influenced by the placement of the tilt sensors. A comparison of displacement and tilt angle monitoring data from the Kaiding landslide confirmed that both tilt and displacement indicators correspond well in terms of early warning timing. The findings validate that surface tilt angle can be effectively used to monitor landslide deformation and provide early warning of slope failure. As a cost-effective monitoring parameter,surface tilt angle holds significant practical importance for landslide monitoring and early warning applications.