Abstract: The step-like evolution of landslide represents the fluctuating behavior of landslides influenced by external factors during the isokinetic deformation phase. Step-like landslide is characterized by extended deformation cycles, intricate mechanisms, and challenges in disaster early-warning. By analyzing the deformation-time curves of step-like landslide, we introduced the concept of “one rainfall process” and defined multiple rainfall intervals in the monitoring sequence. Subsequently, we categorized the warning process into two modes: the previous rainfall-plus the current rainfall pattern, and the current rainfall pattern. With cause-time-space as significant indices for landslide warning, we established a holistic landslide early-warning criterion model, and designed a dynamic early-warning system for Landslide No. 1 at Machi Village as a case study. By correlating geological conditions and monitoring data with a profound analysis of deformation evolution patterns and warning thresholds, we observed that: 1) The landslide deformation mode is predominantly traction-related, demonstrating a typical rainfall-triggered step-like behavior. 2) The effective early rainfall duration is 10 days. The rainfall thresholds are 24 mm and 32 mm respectively under the previous plus current rainfall mode, and 37 mm under the current rainfall mode. 3) With the threshold values for rainfall and displacement rate as the Grade III yellow early-warning central boundary, we established a comprehensive dynamic grading early-warning system that transitions from traditional threshold warning to process warning. This shift enhances the precision and efficiency of landslide prediction and management.

Key words: step-like landslide, landslide monitoring, rainfall process, threshold warning, early warning system