[Objective] Risk monitoring and early warning were studied based on the geological disaster chain of landslides and debris flows in Yuanyang terraced fields in order to improve the accuracy of warnings related to rainfall-induced landslides and debris flow disaster chains and to provide a scientific basis for improving the pertinence of work related to reducing and preventing such disasters. [Methods] This investigation delved into the failure process of disaster chains related to landslides and debris flows in the Yuanyang terraced area through rainfall model simulation experiments. Real-time monitoring of rainfall, volumetric moisture content, and slope deformation coupled with an analysis of the early-warning thresholds for disaster chain risks under various rainfall conditions formed a crucial part of the study. Four specific rainfall conditions 〔i.e., long-term moderate rain (50 mm/h), long-term heavy rain (120 mm/h), cyclic intermittent heavy rain, and drought-sudden heavy rain〕 were established. [Results] The continuous impact of rainfall revealed the development stages of the disaster chain, progressing through surface scouring, creeping, rapid sliding, and debris flow migration until the culmination of the movement process. Slope damage initiated from the foot of the left slope, subsequently affecting the foot of the right slope. Various forms of slope damage manifested themselves under distinct rainfall conditions: transverse cracks appeared in the middle of the slope during heavy rain, resulting in the formation of two landslides (one above and one below); multiple landslides occurred consecutively under moderate rain conditions; and mudslides formed rapidly under drought-sudden heavy rain, covering the longest distances and accumulating over a broader area than observed for other rainfall scenarios. [Conclusion] The main monitoring indicators for disaster chain early warning of landslide and debris flow include cumulative rainfall, duration of rainfall, changes in moisture content, and on-site monitoring of slope deformation development. These monitoring parameters are influenced by various factors such as rainfall conditions, soil properties, slope angle, and external dynamic conditions. Therefore, in practical applications, it is necessary to comprehensively consider these factors.